Know Your Natives – Northern Maidenhair Fern

Northern Maidenhair Fern (Adiantum pedatum) of the Brake Fern (Pteridaceae) family, formerly of the Polypody (Polypodiaceae) family, is a beautiful, shade-loving fern with broad, circular fronds. The genus name is from a Greek word for “unwetted” in reference to the leaves’ ability to shed raindrops. The specific epithet refers to the foot-like shape of the larger pinnules (secondary leaflets). In the U.S., the species is of common occurrence across the eastern half of the country from the Canadian border southward, absent only from Florida and rare in much of the Atlantic and Gulf Coastal Plains. In Arkansas, it occurs across most of the state except for the Mississippi Alluvial and West Gulf Coastal Plains. Favored habitats are rich, deciduous woodlands with well-drained soils.

Photo 1: Fronds are distinctive. Plants prefer shady areas with well-drained mesic soil. Photo – April 19.

Northern Maidenhair, like most Temperate Zone ferns, is deciduous and perennial. Leaves arise from shallow, short-branched, dark brown rhizomes ¼+ inch in diameter––these mostly concealed by a dense tangle of dark brown, wiry roots. In April, pink to reddish fronds (leaves) emerge as coiled “fiddleheads.” Fiddlehead stipes (stalks) are reddish brown, lustrous, and smooth, with scattered, long, light brown, translucent scales. As fronds mature, stipes and rachises become black. Spiky old stipes persist for a year or more. Colonies are slow growing.

Photo 2: Rhizomes are largely concealed by dense wiry roots. Green “spots” at far left and to right, are dormant frond buds on the tips of rhizomes. In this late-in-year photo, only a few fronds remain viable. Photo – December 30.
Photo 3: Coiled fiddleheads––the embryonic form of the developing frond––are shiny and smooth with scattered scales along the stipe. Previous year’s stipes are black and spiky. Photo – May 5.

Mature fronds vary considerably in size, depending on habitat, with a large frond being 2 feet long (including a 15-inch stipe) and a foot wide. The erect stipes divide into a pair of curved, widely divergent rachises that bear 4-6 pinnate pinnae (the primary leaflets), along their convex side. Proximal pinnae may be 8 inches long, gradually shortening to 2 inches distally. Viewed from above, fronds have an attractive, circular shape. Larger ferns may grow to a height of 1½ feet. Fronds are glabrous, except for scales along the lower portion of the stipes.

Photo 4: Stipes divide into a pair of rachises which bear pinnae along their convex side. As shown, solitary pinnules grow directly from the rachis at a point just below the pinnae. Photo – May 8.
Photo 5: Fronds have a circular outline. While the paired rachises recurve in one direction, their distal pinnae recurve in the opposite direction.

The green, photosynthetic unit of Northern Maidenhair Fern is the pinnule, the secondary leaflet. Up to about 20 pinnules are borne on a pinna. Larger pinnules have an inverted-wing shape––the lower margins are entire (uncut) and curved upward while the upper margins are lobed. Pinnules are to ¾+ inch long and ⅜ inch wide, widest near the base. Smaller pinnules, at both ends of the pinna, are stubby to rounded. Solitary pinnules occur on the rachis a short distance below the pinna (see Photo 4). These may be ¼+ inch long and ½+ inch wide with a cuneate base and a fanned apex that is variously divided. Pinnules have thin, wiry, ⅛-inch-long stalks. With winter-kill, light tan crumpled pinnules are retained on the rachis for several months while stipes persist for a year or two.

Photo 6: In winter, dormant plants retain dead fronds. Stipes persist for a year or more. Photo – March 26.

Pinnule venation (see photo 9) is of uniform size and character. In wing-shaped pinnules, a single vein originates at the stalk and, extending along the uncut, lower (proximal) margin, gives rise to further veins that extend, typically forking, into the lobe tips and sori of the upper margin. With solitary fan-shaped pinnules, all veins radiate from the stalk.

Northern Maidenhair Fern has separate fertile and sterile fronds, both with a very similar upper surface. On the lower surface of the fertile fronds, the upper (distal) margin of the pinnules bears 1-8 small, pocket-like clusters of sporangia called sori (singular, sorus). Sori are covered and protected by a narrow strip of the pinnule margin (called a false indusium) that folds back over the sporangia. Indusia are initially pale yellow-green, darkening as sori mature. With sorus maturity in September, indusia dry and loosen, allowing sporangia to discharge minute spores into the air, to be dispersed on breezes.

Photo 7: Above: fertile pinna (lower surface, apex to right) bears sori covered by false indusia (pale green). Below: fertile pinna (upper surface, apex to left) with flattened pinnule lobes––sori are present on the surface underneath. Photo – May 2.
Photo 8: Lower surface of a pinna of a fertile frond, apex to right. Margins of lobes fold over the sori. Lobes are separated by narrow clefts.
Photo 9: When sori have matured, the false indusia shrink away, allowing sporangia to disperse spores. Photo – September 15.

With dispersal of spores, the reproductive activity of the “sporophyte” phase of a fern’s life cycle concludes. In the soil, spores germinate to produce a tiny plant called a prothallus, the “gametophyte” phase. The prothallus, which looks more like an alga than a fern, produces gametes: sperm and egg. Sperm swim through ground moisture to fertilize eggs that remain attached to the prothallus. Fertilization produces a zygote that, in turn, develops into a new sporophyte plant––the plant we recognize as a “fern.”

Northern Maidenhair Fern is a lovely, graceful fern for a shaded mesic site in a naturalistic garden, woodland garden, or even a rock garden. It is suitable for mass-planting or as a specimen plant. It mixes well with other plants of modest height with similar habitat requirements or tolerance. It is slow to spread. Dead fronds provide winter interest with their shiny black wiry stalks and dangling light tan leaves. By spring, except for the stipes, fronds have disintegrated so that springtime clean-up may not be needed.

Photo 10: In this garden site, plants receive only early morning and late evening summer-time sunlight. Other plants shown include Hairy Lip Fern, Texas Dutchman’s Pipe, Cardinal Flower, Tall Anemone, and Silver wormwood – Artemisia ludoviciana subsp. mexicana. Photo – May 8.

An additional species of Adiantum occurs in Arkansas, Southern Maidenhair Fern (A. capillus-veneris). Southern Maidenhair Fern (aka Venus’ Hair Fern) can be distinguished by: 1) preferred habitat being wet vertical cliffs and rock faces but can even establish on masonry walls with lime mortar, 2) stipe undivided, 3) pinnae occurring on both sides of rachises, and 4) pinnules fan-shaped and pendant.

Article and photographs by ANPS member Sid Vogelpohl

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Know Your Natives – Ozark Mock Orange

Ozark Mock Orange (Philadelphus pubescens) of the Hydrangea (Hydrangeaceae) family, formerly of the Saxifrage (Saxifragaceae) family, is a deciduous shrub with bold, showy, four-petaled white flowers. The genus name is said to honor Ptolemy II Philadelphus, pharaoh of Egypt, 283-246 BC. The specific epithet is Latin for “downy.” The common name “mock orange” refers to the flowers’ similar appearance to those of the true orange (Citrus sinensis). Species distribution in the U.S. is intriguing, with both native and introduced populations: Ozark Mock Orange grows primarily from eastern Oklahoma to Tennessee and sporadically in adjoining states; isolated populations are also to be found from as far west as Wyoming to Massachusetts in the East. In Arkansas, plants occur primarily in the Ozark Highlands and Boston Mountains, higher elevations of the Arkansas Valley, and in the Ouachita Mountains. Habitats include dry-mesic to mesic, loamy to rocky soils and rock outcrops of open woodlands and woodland borders, as well as stream banks. The species is also known as Downy Mock Orange, Gray Mock Orange, and Hoary Mock Orange.

Photo 1: Shrubs have showy white flowers. Photo – May 12.

The open to compact base of this deciduous shrub has a few to numerous stems of various ages. While young root-shoots tend to be slim and erect, older stems are spreading and arched. A few root-shoots may sprout a foot or more away from a parent plant and become clonal plants. In about the third year, thin bark may split but mostly remains tight on all but the oldest stems. Shrubs typically reach 8 feet tall but may be 12+ feet.

Photo 2: Stems of various ages form the open base of this shrub. Bark exfoliation becomes more evident on the oldest stems. Photo – December 2.

Overwintering terminal and lateral buds are hidden. New branches, growing from these buds, may be strictly vegetative or fertile, with both leaves and flowers (see Photo 1). Additionally, new robust vegetative stems, with rapid growth (2 to 6 feet) in their first year, sprout directly from the rootstock and along the higher portion of arched mature stems. With lateral leaves having a single axillary bud, if that bud produces a flower, that portion of the twig dies after producing fruit. New stems, branches and twigs, typically glabrous, change from pale green to reddish to tannish brown, within several months. Stem pith is white.

Photo 3: This sterile branch at the end of the growing season bears terminal and axillary buds that are hidden over winter. Photo – September 13.
Photo 4: Current year’s growth (branches to the left) emerged from hidden axillary buds. The first node on branches (arrows) marks early growth of hidden buds. Stems have a white pith (diameter of one shown is 5/16 inch). Photo – December 11.

The simple petiolate leaves occur in opposite decussate pairs. Leaf pairs on twigs quickly decrease in size, distally becoming early-deciduous linear bracts that subtend the uppermost pair of flowers. Larger leaves are broadly ovate with a short-acuminate apex and rounded base, while smaller leaves are narrowly elliptic. A larger leaf may be to 3½ inches long, with a ¼ inch petiole, and 2⅜ inches wide. Elliptic leaves tend to have entire margins; margins of ovate leaves tend to have a half-dozen or so sharply pointed, shallow teeth along the distal half. Leaves are green above and lighter green below. Venation is pinnate, with secondary veins arching toward the apex. Dense pubescence occurs on the lower surface of blades and petioles. The upper leaf surface is glabrous with an occasional hair along the main veins.

Photo 5: Smaller leaves are elliptic; larger leaves are broadly ovate. Paler lower leaf surfaces shown on right. Lowermost secondary vein pairs are less distinct than those above. Photo – October 6.
Photo 6: Lower leaf surface (below) has dense pubescence while upper surface is nearly glabrous and feels smooth.

In late April into May, terminal and axillary, perfect flowers (with male and female parts) develop at the tips of new-growth twigs. Three to 11 flowers may occur on a twig, so that the inflorescence appears raceme-like. Flowers are 1+ inch wide and long with an inferior ovary beneath a perianth of 4 triangular sepals and 4 overlapping, somewhat cupped, showy white petals. Stamens are numerous: 30+. Four white styles are united below, divided and spreading above, with elongate, light yellow stigmas extending outward from the flower center. Stamens, with strongly ribbed anthers and yellow pollen, attach in a double row around the rim of the ovary. The slender white filaments are erect, so that the anthers are positioned at or just below the stigmas. Pedicels and ovary are glabrous. Sepals are covered with downy pubescence within. Following anthesis, petals, stamens and stigmas quickly drop off .

Photo 7: Uppermost pair of buds is axillary to early-deciduous linear bracts, while lower bud pair is axillary to elliptic leaves. Partially open calyx of the terminal flower exposes dense downy pubescence of the upper surface. Photo – April 6.
Photo 8: Sterile branch at left terminates with a bud and will lengthen in the next growth year. Fertile twig, at right, terminates with an inflorescence. The flowering portion of fertile twigs dies after bearing fruit. Photo – May 2.
Photo 9: Ovaries are rimmed by a calyx of triangular sepals. Lower surface of leaves and petioles is pubescent. Photo – May 10.
Photo 10: This single stem has several fertile twigs. Petals are obovate to oval.
Photo 11: This flower has about 35 stamens and 4 styles (united below and spreading above) topped with 4 elongate, light-yellow stigmas.

Fertilized flowers produce upright urn-shaped capsules that are about ¼ inch long and wide. Capsules mature from pale green to golden brown to dark brown. Sepals and the united styles are persistent. By mid-September, capsules are divided into bulging, pie-shaped segments that split across the top into 4 sections. Seed attachment is along a central (axile) placenta in each chamber. After splitting, capsules persist and gradually deteriorate over late fall into the winter months. Seeds are released from the top of the capsule. The numerous elongate golden to reddish brown seeds, to ⅛ inch long, have an irregular fusiform shape.

Photo 12: Inferior ovaries with persistent sepals and style base. Only the margins of sepals remain downy. Photo – June 24.
Photo 13: Mature capsules are packed with seeds. Current year branches have flattened sides. Portions of branches that produce flowers die after fruiting. Photo – September 17.
Photo 14: This capsule has been split to show internal chambers, including the axile placenta. Seeds have a filiform shape.

Ozark Mock Orange in a garden or natural area is most notable for the cascades of large showy white flowers. Young shrubs are mostly upright while older stems of mature shrubs become spreading and arching. Leaves are not showy in fall. Clonal offset plants are fairly easy to transplant. Best flowering occurs in more sunny sites.

Two additional species of mock orange have been recorded in Arkansas: the native Hairy Mock Orange (Philadelphus hirsutus) and the adventive-native Appalachian Mock Orange (Philadelphus inodorus). Ozark Mock Orange can be distinguished from Hairy Mock Orange by its 1) hidden axillary buds, 2) larger flowers with spreading stigmas, and 3) leaves that feel smooth on their upper surface. Ozark Mock Orange can be distinguished from Appalachian Mock Orange by its 1) smaller flower petals and fewer stamens, 2) larger leaves that are broadly ovate, and 3) pubescent leaves.


Article and photographs by ANPS member Sid Vogelpohl

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Know Your Natives – Hairy Mock Orange

Hairy Mock Orange (Philadelphus hirsutus) of the Hydrangea (Hydrangeaceae) family, formerly of the Saxifrage (Saxifragaceae) family, is a deciduous shrub with rather large, showy, four-petaled white flowers. The genus name is said to honor Ptolemy II Philadelphus, pharaoh of Egypt (283-246 BC). The specific epithet is Latin for “hairy.” The common name “Mock Orange” refers to the flowers being somewhat similar to those of the true orange (Citrus sinensis). In the U.S., along with a disjunct distribution centered in north-central Arkansas, the species is found principally in an area centered on the Southern Appalachians. In Arkansas, it occurs primarily in the Boston Mountains and Arkansas Valley, with a few south-central Ozark Highlands occurrences. Habitats include dry to mesic rocky outcrops, ledges, talus slopes, and seepage areas, on various rock types, on open or wooded sites. It is also known as Cliff Mock Orange.

The shrub has a few to numerous, erect to spreading stems that become arching in age. A few clonal plants, growing from shallow root extensions, may appear a foot or more from the base of the parent plant. Beginning in the second growth year, the bark exfoliates in thin strips. Although typically under six feet tall, stems may reach ten feet in ideal habitats. Shrubs tend to be somewhat taller than broad and may have only a few large stems or large stems intermixed with root shoots, growing from a compact clump.

Pointed terminal and lateral buds are covered with tight overlapping brown scales. Terminal buds produce a leafy branch which may end with a pair of opposite leaves or a floral cluster. Lateral buds produce either a sterile leafy branch or a short floral branch, with or without a subtending pair of leaves. Since floral clusters are terminal, the next year’s growth of floral stems occurs from lateral buds. New, rapidly growing, robust branches sprout along arching mature stems or directly from the rootstock. Mature shrubs tend to be open with most active growth and flowering at the perimeter.

New branches and twigs are pale green with appressed, dense, soft pubescence, becoming brown to reddish brown and glabrous within several months. With springtime growth, the brown bud scales persist. Additionally, several elongate, leaflike bracts occur near the base of new branch growth. Pubescence of new twigs extends onto the leaves and inflorescences. Stem pith is white.

Photo 1: These shrubs, in a sunny roadcut, have a few fairly straight stems with limited branching. New growth will arise from terminal and lateral buds. Photo March 15.
Photo 2: These shrubs, growing in a cliffy shaded ravine, have a combination of long arching older stems mixed with younger basal shoots. Arched stems on right have produced arched branches. Photo – March 23.
Photo 3: Lateral buds on this branch segment produced only leafy branches. More vigorous branch-growth occurs on the sunnier side of branches. Photo – April 24.

Simple, opposite, petiolate leaves vary from lanceolate with an acuminate apex (smaller leaves) to ovate-elliptic with an acute apex (larger leaves). A larger leaf may be 3¾ inches long, including a ¼ inch petiole, and 1¾ inches wide. Leaf bases are acuminate to nearly rounded. Leaf margins, mostly in the distal half, have a few widely spaced, blunt or sharp teeth. Venation is pinnate, the secondary veins arching toward the leaf apex, with the lowermost pair most prominent. Dense appressed pubescence covers the entire lower blade surface and extends along the lower side of the petiole. The upper surface can feel a bit rough, with shorter, sparser pubescence. Leaves are somewhat leathery (coriaceous).

Photo 4: Simple leaves vary from lanceolate (on floral twigs) to ovate-elliptic. Leaves on right show their lower surface. Margins may be entire or sparsely toothed. Bumps are insect galls. Photo – October 7.
Photo 5: Lower leaf surfaces and petioles have dense appressed pubescence. Midrib and lowermost pair of secondary veins are prominent. Photo – May 2.
Photo 6: Folded leaves: lower surface below, upper surface above. Hirsute pubescence of upper surface feels somewhat rough. Tertiary veins are reticulated. Photo – October 7.
Photo 7: Pointed terminal and axillary buds are protected by overlapping scales. Leaf lower surfaces shown on right. Photo – August 25.

The inflorescence is borne on new-growth branches in late April into May. Terminal and axillary, perfect (with male and female parts) flowers occur singly or in clusters of 2-5. They are about ¾ inch long and wide, with an obconic round-topped inferior ovary, a calyx of 4 triangular sepals, a corolla of 4 white petals, 20± stamens (along with a few staminodes), and 4 united white styles with yellow stigmas that form a sturdy club-like central structure. Stamens, with strongly ribbed yellow anthers, attach single-file around the perimeter of the calyx. The slender white filaments curve inward so that the strongly ribbed, football-shaped, pale yellow anthers are positioned above the stigmas. The cupped, obovate petals have overlapping, distally recurved margins. Ovary and sepals are densely hairy. While stamens quickly drop off after anthesis, the styles persist until fruiting capsules open, and the sepals remain until capsules disintegrate.

Photo 8: In sunny sites, shrubs (also in Photo 1) may bear many flowers. Some branches, at top of shrub, did not bear flowers so that height of plant increased. Blackberries in flower at lower right. Photo – May 3.
Photo 9: Calyxes atop the inferior ovaries comprise triangular sepals. Brown bud scales and green lanceolate scales can be seen. Dense pubescence extends from calyx and ovary onto the pedicels and twigs. Photo – April 24.
Photo 10: Flower clusters are terminal and lateral. Lateral twigs typically lack leaves or have a single opposite pair. Terminal branch growth, ending with flower clusters, tends to bear several pairs of leaves. Photo – May 5.
Photo 11: Cupped obovate petals have overlapping edges and recurved upper margins. A few lanceolate bracts occur along the pubescent pedicels. The two-year old branch (brown) has thin exfoliating bark.
Photo 12: With petals removed, the pubescent upper surface of sepals can be seen. Filaments and styles are white. Stamens surround the shorter, united styles which are topped by 4 united yellow stigmas (see arrow).

Fertilized flowers produce upright capsules that are about 3/16 inch long and wide. Capsules mature from green to dark brown, retaining the obconic shape of the ovary. By August, the top of the capsule is divided into bulging, pie-shaped segments that open into 4 seed chambers. After dehiscing, capsules persist and gradually deteriorate over the winter months as seeds are dispersed. The elongate tan seeds, 1/16 inch long, have an irregular fusiform shape. Seed attachment is along a roughened central axile placenta in each chamber.

Photo 13: The encircling stamens arch over the central style/stigma unit. The 4 united stigmas are visible in the upper flower. In lower cluster, with stamens having dropped, the style/stigma units remain attached to maturing fruits. Photo – May 12.
Photo 14: Tops of dry fruits, with 8 pie-shaped segments, open into 4 chambers. Sepals are persistent. Hirsute pubescence remains on upper leaf surface. Photo – September 20.
Photo 15: Chambers have a roughened central placenta (see arrow) which bears numerous seeds with an irregular fusiform shape. Squares = ¼ inch.

In a sunny garden, the flowers of Hairy Mock Orange are lovely. Plants grow well in well-drained rocky soils. They may develop into open upright shrubs with a few major stems or multi-stemmed shrubs with tall arching branches crowded with suckers. The base of a shrub tends to be compact. Any nearby clonal plants, if necessary, can be removed. The small leaves are not showy in fall. Hairy Mock Orange is ideal for a sunny open woodland or woodland border.

Two additional species of Mock Orange have been recorded in Arkansas, namely, the adventive-native Appalachian Mock Orange (Philadelphus inodorus) and Ozark Mock Orange (Philadelphus pubescens). Hairy Mock Orange can be distinguished by 1) smaller size, 2) leaves with three prominent veins (midrib and lowermost pair of secondary veins), 3) densely pubescent new-growth twigs, 4) hirsute upper leaf surfaces, 5) exposed terminal and axillary buds, and 6) united stigmas.

Article and photographs by ANPS member Sid Vogelpohl

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Know Your Natives – Winged Sumac

Winged Sumac (Rhus copallinum*) of the Cashew (Anacardiaceae) family is a deciduous shrub or small tree that forms clonal colonies from lateral roots. Rhus is the old Greek and Latin name for sumac. The specific epithet, based on an Aztec word, translates as “resinous,” in reference to its sap, or copal, a name given to tree resin. This is a common species throughout much of the U.S., from central Texas, southeastern Nebraska, and central Wisconsin eastward. Alternate common names include Shining Sumac, Dwarf Sumac and Flame-Leaf Sumac. Habitat ranges from full to partial sun on various soils––sandy to rocky, dry to mesic––on prairies, woodland edges, fencerows, roadsides, burned areas, and abandoned fields. Winged Sumac is an early successional species and is considered to be invasive in managed, tall-grass prairies.

Photo 1: This clonal colony, in a prairie-like setting, is in an area subject to controlled burns. Photo – October 30.

The parent tree of a clonal colony has a taproot with shallow lateral roots that may extend for many feet. Clonal trees, or root sprouts, grow from adventitious buds along the upper side of the lateral roots. Vegetative clones may occur as thickets or as widely scattered trees. Lateral roots remain viable throughout the short lifetime (less than 20 years) of a clonal colony. Roots that are slightly cut or flexed slowly exude a small quantity of white, resinous sap. Wood of the stems is white, surrounding a tan pith.

Photo 2: This parent tree (3½ feet tall) has a stubby taproot and four lateral roots, one of which was uncovered for 14 feet, but extended farther. Lowermost point of this taproot was dead, suggesting that the taproot of parent plants becomes insignificant with development of lateral roots.
Photo 3: Lateral roots are variable in diameter. Arrows indicate stems of clonal trees or root sprouts. Sprouts do not develop taproots. Note that fibrous roots occur along the main lateral root and on dead-end branches.
Photo 4: This trunk segment (above) and lateral root segment (below) were taken from the tree shown in Photo 2. White resinous sap exudes from injuries on the trunk and root. Trunk and root are roughened by numerous lenticels.
Photo 5: Mature trunks (of trees in Photo 6) are roughened by a concentration of lenticels and slightly exfoliating bark. Circumference of tree on right is 17½ inches. Photo – November 8.

Stems (trunks) of clonal trees in their first one to two years of growth are straight and unbranched, elongating from the terminal bud only. By the third year, lateral stems (branches) grow from one to several of the uppermost axillary buds. When a clonal tree is mature enough (fourth year?) to produce an inflorescence (always terminal), lateral buds immediately below the inflorescence produce new branches. Growth rate of stems varies widely, from less than an inch to several feet, as determined by specific site conditions (soils, moisture, shading) and the age of the clonal tree. Mature trees in an open space have a broad, rounded top, while crowded trees are slender with lower branches lost due to shading. Trees typically reach a height of 10 to 12 feet, but may reach 30+ feet. Entire clonal colonies die when shaded by a closing forest canopy.

Photo 6: These several tall ( 36+ feet) Winged Sumacs, at center of photo, are part of a larger clonal colony and are now struggling to survive in a closing forest canopy. Photo – November 8.

New, pale green stems are densely covered with velvety white hairs (puberulent) that extend onto the petioles (leaf stalks). This pubescence persists as stems age and darken. Small dark lenticels (air pores) on current-year’s stems become more numerous from year-to-year, giving the thin, gray to reddish bark of larger trees a rough, pustulate appearance. Trunks often have a few large white splotches.

Photo 7: New stems grow from axillary buds immediately below last year’s fruit cluster. Remnants of a two-year-old infructescence can be seen at lower right. Photo – April 14.

The alternate, odd-pinnately compound leaves bear 5-25 leaflets. Leaves grow to 12 inches long (including a 2½ inch petiole) and 2 inches wide. Petioles may be reddish. Sessile to sub-sessile leaflets, to 3½ inches long and 1½ inches wide, are lanceolate to ovate-lanceolate, with a rounded to attenuate base and acute or acuminate tip. Leaflets can be asymmetric across the midrib with the upper half wider. Margins are typically entire (smooth), though slight serrations may occur distally. The leaf rachis––the midrib between the paired leaflets––is prominently winged, the wings from ⅛ to ⅜ inch wide. A stubby wing also occurs at the base of the terminal leaflet. Leaflets and wings are dark, shiny green above and dull, yellowish green beneath. Upper leaf surface is mostly glabrous, the lower surface densely pubescent with short spreading hairs. At the end of the growing season, small axillary buds for next year’s new lateral branches are somewhat obscured by slightly elevated, crescent-moon-shaped leaf scars.

Photo 8: The odd-pinnately compound leaves have a dark shiny green upper surface and a dull yellowish green lower surface. Leaf at left is 11¾ inches long and 7 inches wide. Photo October – 12.
Photo 9: While upper leaf surfaces are generally glabrous, lower surfaces are densely pubescent. Length of wing at center of photo is 1¼ inch. Photo – November 5.

In June and into July, terminal buds produce large, upright, conic, densely pubescent, branching panicles. Flowers are closely packed. Yellowish green corollas, ⅛ to 3/16 inch across, are set in a dark green, bowl-shaped calyx with 5 triangular lobes.

Winged Sumac is a dioecious species––unisexual flowers (pistillate or female flowers and staminate or male flowers)––occur on separate plants as well as on separate clonal colonies. In the case of a fully dioecious species, pistillate flowers lack stamens and staminate flowers lack pistils. However, with Winged Sumac, pistillate flowers may have rudimentary (infertile) stamens and staminate flowers may have rudimentary pistils. The female flowers have 3 stocky, spreading styles with round stigmas atop a pubescent ovary with a single ovule. The male flowers have 5 stamens that extend well above the corolla so that the relatively large, lobed, light yellow anthers are well exposed. Pollen is dark yellow.

Photo 10: This compound panicle bears pistillate flowers. The infructescence from the previous growth-year remains, the fruits uneaten. Note that the reddish stems and petioles remain pubescent. Photo – June 20.
Photo 11: These pistillate flowers have 3 styles and 5 infertile stamens. Pubescent ovaries of two flowers at upper right can be seen. Lobes of a dark green calyx can be seen at right center. Photo – June 20.
Photo 12: This compound panicle bears staminate flowers. Viewed from a distance, such panicles appear to be yellowish. Photo – June 20.
Photo 13: Staminate flowers have 5 slender stamens topped with prominent, ribbed anthers. Flower at upper left has an infertile pistil. Pollen is yellow. Photo – June 20.

Female trees may produce large quantities of fruit on eventually drooping panicles. Clusters, 6+ inches long, persist into the following spring and remnants may persist into the second spring. The ovoid drupes, to 3/16 inch long, are reddish purple at maturity in mid-August and become brown and black as they shrivel over winter. Fresh drupes are covered with dense spiky white hairs. Tan smooth stones (to ⅛ inch across) have a flattened pea shape.

Photo 14: This tree has especially long stem segments and many large clusters of fruits. Trees at lower right and leaves at upper left are Serviceberry. Photo – October 12.
Photo 15: For this display, small lateral clusters were pulled down to loosen up the tight compound panicle. Photo – October 17.
Photo 16: Densely pubescent fruits are red to reddish purple at maturity. Uppermost fruit is 3/16 inch across. Stones are ⅛ inch across. Photo – October 17.

In considering Winged Sumac for a garden, there are a number of characters to recommend it: 1) an easily grown small tree with attractive green leaves, 2) copious showy panicles of tiny flowers that benefit insects, 3) fruits that are an important source of food for many birds and small mammals, and 4) excellent fall color. With pruning of lateral roots to remove excess root sprouts, a desirable ornamental plant may develop. Without root pruning, Winged Sumac is excellent for naturalizing larger areas and for erosion control on slopes. It may adapt to a container.

Four additional species or varieties of Rhus occur in Arkansas: 1) Fragrant Sumac (Rhus aromatica var. aromatica), 2) Tall or Midwestern Fragrant Sumac (Rhus aromatica var. serotina), 3) Smooth Sumac (Rhus glabra), and 4) Skunk-Bush Sumac (Rhus trilobata var. trilobata) (Little River County only). Only Smooth Sumac has similar leaves, inflorescence, and fruit. It can be distinguished by: 1) lack of wings along the leaf rachis, 2) fully serrated leaflets, and 3) upright mature fruited panicles.

Photo 17: Winged Sumac (left) and Smooth Sumac (right) both have excellent fall color. These trees re-grew after being cut and are thus more shrub-like. Photo – November 7.

*Some authorities have identified two varieties of Winged Sumac: 1) Eastern Winged Sumac (Rhus copallinum var. copallinum) which has 11-25 leaflets with attenuate bases and entire margins and 2) Western Winged Sumac (Rhus copallinum var. latifolia) which has 5-13 leaflets with rounded bases and margins that may be entire or serrate in their upper portion. The distribution of these varieties in Arkansas has not been well-mapped.

Article and photographs by ANPS member Sid Vogelpohl

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Know Your Natives – Carolina Buckthorn

Carolina Buckthorn (Frangula caroliniana, formerly Rhamnus caroliniana) of the Buckthorn (Rhamnaceae) family is an elegant, thornless (!), deciduous shrub or small tree, with simple shining leaves and red to black berry-like fruits. (The tiny, whitish flowers are easily overlooked.) The genus name originates from the word “frangible” meaning “easily broken.” The specific epithet recognizes that the species was first described from specimens collected in the Carolinas. It occurs primarily from central Texas to central Missouri, east to Virginia and central Florida. In Arkansas, plants are found statewide except for portions of the Mississippi Alluvial Plain. Habitats vary, with soils acid to limy, moist to dry, in sun to part shade, in woodland margins, glades, bottomlands and stream terraces. The species is also known as Indian-Cherry.

Photo 1: Lower portion of this tree, positioned at a woodland edge, is compact and leafy as compared to the more sparse upper portion that extends into the overstory. Top of tree indicated by arrow. Photo – July 21.
Photo 2: This understory tree, located among large canopy trees of other species, has an estimated height of 36 feet and a spread of 19 feet. Dead limb on right is 6 feet above the ground. Photo – October 21.

Carolina Buckthorn is typically 10 to 15 feet tall, but may reach 30+ feet, especially on partially shaded sites. On sunny sites, plants develop a denser limb structure and often become rather shrubby. Despite the common name, none of the “Buckthorns” segregated from Rhamnus into the genus Frangula are armed with thorns. In addition, Frangula species are characterized by naked winter buds, that is, buds composed of tightly folded miniature leaves that are not protected by scales––a distinctive character useful for winter identification. Young branches have dense, minute, appressed pubescence (extending onto leaf petioles) that is lost by mid-growing-season. Twig color changes from pale green to tan and ultimately to gray as branches mature. Bark is thin and smooth with slightly raised whitish lenticels and leaf scars as well as whitish splotches and short tight fissures.

,Photo 3: The root of this 5-foot tree suggests that the roots of larger trees would be similar, that is, with major roots extending laterally as well as descending to depth.
Photo 4: A display to show changes of color and texture as branches and trunks mature. Diameter of trunk at left (same plant as shown in Photo 3) is ⅝ inch. Branch at far right is current year’s growth with leaves removed. Leaf at right is 6 1/4 inches long and 2 1/4 inches wide. Photo – October 17.
Photo 5: This trunk of a 36-foot tree (also shown in Photo 2) is mostly smooth with whitish splotches and slight fissuring. The trunk has a circumference of 15¾ inches at 5 inches above ground.
Photo 6: Terminal and lateral buds are composed of pubescent miniature leaves which are not protected by scales. With leaves removed, the three vascular bundles can be seen in the leaf scar. Photo – October 6.

Alternate elliptic to obovate-elliptic leaves, with a shiny dark green upper surface and a dull pale green lower surface, have a rounded to cuneate base and an apex that may be acuminate, acute or obtuse. A large leaf may be 6½ inches long, including a ⅝-inch petiole, and 2 inches wide, the largest leaves occurring toward the branch tips. Venation is offset-pinnate, with 8-10 pairs of prominently straight and parallel secondary veins that bend forward near the leaf margin. Margins are irregularly and obscurely crenate. Persistent dense minute pubescence of the petiole extends onto the veins of the blade beneath, with longer scattered hairs between the veins. Upper surface of the leaves feels smooth; lower surface feels corrugated, due to expressed lateral veins. Leaves droop in dry spells, but quickly rebound with renewed moisture. Leaves become yellow to bronze in fall.

Photo 7: The simple, elliptic to obovate-elliptic leaves are shiny dark green above and dull pale green beneath. They have equally spaced, perfectly parallel secondary veins that extend toward the leaf margin. Photo -May 28.
Photo 8: Secondary veins extend to near the leaf margin where they align with the margin and interconnect. Margins are minutely irregularly notched. Upper surface shown on left and lower surface on right. Photo – October 17.

The inflorescence, from May into June, consists of axillary umbels of tiny (⅛ inch wide and long), pale green to whitish flowers on short, ascending pedicels. A peduncle may support 1-10 flowers. Peduncles, pedicels, and calyxes are densely puberulent.

Photo 9: Umbels of 10± flowers are axillary to current-year’s leaves. Naked buds for the next year’s growth can already be seen at top of photo. Leaves are alternate or rarely subopposite. Photo – June 3.

The inconspicuous, perfect (with male and female structures) flowers have a small, campanulate (bell-shaped) hypanthium, bearing 5 triangular sepals, 5 petals, and 5 stamens. Petals are smaller than sepals, and the stamens are positioned opposite the petals––a very unusual morphology. The compound pistil in center bears an undivided style with sunken stigmas. Flowers in bud form a 5-sided pyramid and, in bloom, spread wide to form a star. When lobes of the perianth open, the petals are wrapped around the stamens. With the petals unfurled, the pale yellowish-green, strongly ribbed anthers are exposed.

Photo 10: Two small umbels are shown on left and a larger umbel on right. Puberulent peduncles and pedicels are straight and stout. Exterior surface of hypanthium and lobes are similarly pubescent. Photo – May 28.
Photo 11: Inconspicuous petals initially shroud the stamens (see open flowers on left and right). Several flowers have progressed to early fruits. Dense minute pubescence of the petioles can be seen. Photo – May 28.
Photo 12: Petals and stamens are positioned between calyx lobes. Three fused carpels of the pistil form a central column topped with three round, sunken stigmas (flower at upper right). Photo – June 28.

Trees in favorable sites can produce a copious quantity of fruits (drupes). The spherical, ⅜-inch drupes change from green in July, to red in August, and black in October. The black mature drupes have a tiny stubby point at their apex (scar of style). The thin-skinned mature drupes contain three relatively large stones (¼ inch x ⅜ inch) that are pressed together in a white, rather pungent flesh. The black skin of fruits may cause the flesh of a crushed fruit to be purplish The dark brown stones, with tan bases, have a rounded side and two flattened sides with a slight rib separating the flat sides. Fruits, supported by stout peduncles and pedicels, tend to be readily visible between leaves.

Photo 13: Initially green, fruits are axillary on current-year’s growth. Leaves tend to be larger at and near the ends of branches. Photo – July 21.
Photo 14: Fruits transition from green to red in late summer. Shiny leaves have prominent, equally spaced pinnate venation. Photo – August 23.
Photo 15: Fruits transition from red to black at maturity in the fall. Leaves become yellow or sometimes bronze in fall. Photo – September 21.
Photo 16: The black fruits each contain three stones which are pressed together (shown at right) so that each stone has a rounded side and two flattened sides. Squares = ¼ inch. Photo – October 6.

Carolina Buckthorn may be an excellent choice for a partially sunny garden border or natural area. With its glossy green leaves and its red to black fruits, it is showy over the entire growing season. Leaves tend to be retained during dry periods, and, though becoming limp, quickly respond to wetter conditions. Rate of growth, size and form vary considerably depending on a tree’s number of sun-hours. Plants in full sun tend to be more densely branched and produce a larger quantity of fruits. Carolina Buckthorn is fairly aggressive at self-seeding so that seedlings may need to be controlled. When other choices diminish, fruits are appreciated by many birds and small and large mammals.

Carolina Buckthorn is the only species of the genus Frangula that occurs in Arkansas. A native species of the same family and somewhat similar character is Lance-Leaf Buckthorn (Rhamnus lanceolata) which occurs in the Ozark Mountains in the northern two tiers of counties in Arkansas. Lance-Leaf Buckthorn is a shrub to 9 feet tall, with smaller and usually more lanceolate leaves, smaller glabrous clusters of 4-petaled, separate staminate and pistillate flowers, and buds with scales. Two non-native species of the genus Rhamnus have been reported escaping at a few sites in the Ozark Mountains, namely European Buckthorn (Rhamnus cathartica) and Dahurian Buckthorn (Rhamnus davurica). These non-native trees have mostly opposite and more rounded leaves; short, thorn-tipped twigs and larger branches; and fruits each with either 3-4 stones (European Buckthorn) or 2 stones (Dahurian Buckthorn).

Article and photographs by ANPS member Sid Vogelpohl

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Know Your Natives – Hairy Bush Clover

Hairy Bush Clover (Lespedeza hirta) of the Pea or Legume (Fabaceae) family is a perennial herb with stems to 3+ feet tall, bearing tightly clustered racemes of small creamy white flowers. The genus name is dedicated to Vicente Manuel de Cespedes (an early botanical text misspelled his name as “de Lespedez”), governor of the Spanish province of East Florida, 1784-1790, during the botanical travels there of Andre Michaux who described the genus. The species name is from the Latin word hirtus for “hairy,” in reference to the plant’s dense pubescence. In the U.S., the species occurs across a large area from eastern Texas and southern Michigan, east to Maine and Florida. In Arkansas, it occurs mostly statewide with the exception for portions of the Mississippi Alluvial Plain. Habitats are sunny to partially sunny areas in sandy to rocky, dry to moist soils, such as open woodlands, prairies, and glades.

Photo 1: Growing in full sun on a steep rocky slope, this plant is especially bushy due to early stems having been browsed by deer. Photo – October 5.

Plants produce several to many slender, round stems from a relatively short taproot and wide-spreading lateral roots. Stems average about 3 feet long but may reach 4½ feet. A 4-foot plant may have stems ¼ inch thick near the base. Smaller plants tend to branch only in the inflorescence, while more robust plants may have branches from mid-stem to 16 inches long with secondary branches of several inches. In general, lower branches are shorter than upper branches. Most branches terminate with an inflorescence. Stems are erect but become broadly arched as height increases and with the weight of the inflorescence. Stems and branches are uniformly covered by dense, short, soft, spreading pubescence. Stems are brittle and snap easily.

Photo 2: This plant, with six living stems to 3½ feet long, has a central taproot (see red arrow) and several widely spreading near-surface lateral roots. Bases of current-year stems bear buds for next year’s growth. Width of the root system shown in photo is 8 inches. Photo – October 10.
Photo 3: Spring growth is from the living base of previous year’s persistent dead stems. At this stage and throughout the growth cycle, dense pubescence covers the plant. Photo – March 29.

Compound, trifoliate, alternate leaves are regularly spaced from the base of the stem into the inflorescence. Both lateral and terminal leaflets are ovate to orbicular, green above, pale and yellowish beneath, with apexes and bases equally rounded. Leaves may be as large as 2+ inches long, including a ½-inch petiole, and 2 inches wide. The tip of the leaflets is typically mucronate––bearing a minute spine-like extension of the midrib. Like the stems and branches, the petioles, petiolules (leaflet stalks), rachises, and the undersurface of the leaflets are pubescent with rather softly spreading hairs. Pubescence of the upper leaflet surface is sparser and more appressed. Leaf bases bear a pair of weak greenish spine-like stipules (to ⅛ inch long) which quickly become brown but often remain attached. Venation is pinnate with upper veins weakly recessed and lower veins strongly expressed. Leaflet margins are entire (uncut) and strongly revolute (down-turned). With stem age and drying soils, leaf-drop proceeds upwards from the stem base and may extend into the inflorescence

Bloom time is September into October. The inflorescence comprises short (to ¾ inch), dense racemes of small, short-stalked flowers at the tips of the stems and branches. Racemes that are lower on the plant are subtended by a leaf, while those above are subtended by a pair of tiny broadly triangular bracts. Racemes may be sessile or on straight peduncles to 1½ inches long. They bear up to about 20 flowers. Often, especially at the top of the plant, racemes become densely spaced, terminating the stems in tight clusters of 15± racemes. Drying soil causes some racemes to not develop fully, resulting in naked peduncles during the growing season.

Photo 4: The trifoliate leaves bear ovate to orbicular leaflets. Relative length of petioles and rachises is variable––on leaves shown, they are about equal. Leaflets may have tiny apical mucros.
Photo 5: Leaflets have entire (uncut) revolute margins and pinnate venation. As shown, several peduncles did not develop or retain flowers, due to drying soil. With this reclined pair of branches, leaves and inflorescences have re-oriented toward the sun.
Photo 6: These racemes, oriented toward the sun, are at the early stage of blooming. Flowering has begun as racemes continue to lengthen, and developing flower buds become increasingly pointed.

Flowers have a bilaterally symmetrical, pea-like structure typical of the majority of genera in the Legume family: an upright broad banner petal, a pair or elongate wing petals, and a pair of keel petals fused together along their lower margins to form a boat-shaped keel. Wing and keel petals together form a central enclosure that conceals the pistil (ovary + style + stigma) and stamens (filaments + anthers). The corolla is creamy white, the banner with two sets of purplish red “pollinator guides” that radiate from just above the pale green throat and a central crease that extends out of the throat to a slight apical point. The small flowers are ¼ inch long and, when viewed from the front, 3/16 inch tall and ⅛ inch wide. The calyx, 3/16 inch long, has 5 narrow-elongate, sharply pointed, triangular lobes. Calyx lobes, fused at their lower third, are positioned with an upper pair behind the banner, a pair to the sides, and a single lobe directly below the keel. All lobes are pressed against the corolla. The calyx is densely covered with long hairs. Of the 10 slender staminal filaments, 9 are fused in their lower half and tightly encircle the pistil, forming a sort of “column.” The tenth free-standing stamen is positioned between the pistil and banner. Flattened globular anthers, at the apex of the greenish-white filaments, are yellow with a surface that is irregular with intertwined ridges. The ovary bears a short greenish white slender style tipped with a small circular stigma. Towards the distal end of the stamen-pistil column, the column arches upward so that anthers and stigma are positioned just inside a slit at the tip of the keel.

Photo 7: The small flowers, with stubby pedicels, are creamy white with purplish red pollinator guides across the broad banner. Appressed pubescence on upper leaf surface (at lower left) may be seen as a sheen. Photo – September 15.
Photo 8: Dense pubescence extends from stems onto peduncles (a segment shown at lower right), pedicels and calyxes. (Two racemes are shown, their apexes to left.)
Photo 9: While racemes lower in the inflorescence are subtended by leaves, closely spaced upper racemes are subtended by pairs of broad short bracts and the flowers are subtended by a pair of elongate bracts. As shown, the short and elongate bracts are brown.
Photo 10: Note 1) size of calyx relative to corolla, 2) arrangement of the 5 calyx lobes on right flower, 3) pair of bracts at base of calyx on left flower, and 4) relative size, shape, and orientation of wing and keel petals––wing petals spread (left) as flower develops.
Photo 11: In main photo, wing and keel petals have been spread to expose the stamen/pistil column (with 9 fused stamens). Inset shows the single free-standing stamen (diverted down from the column from its natural position projecting forward with the other stamens) and the clawed wing and keel petals (shown combined).

Fertilized flowers produce thin, flat, oval pods or legumes with an extended, sharply tapered beak (remnant of the style). Pods are densely pubescent. With fruit maturity, calyxes and pods become the same rich brown color. Pods extend beyond calyx lobes. Each dry pod contains a single dark brown seed <⅛ inch long with a somewhat flattened oval shape and smoothly rounded edges. Dried calyxes persist into winter.

Photo 12: Pods partially extend out of the calyx (red arrow). Cluster at upper right is composed of four or more racemes. Photo – October 4.
Photo 13: Pods and calyxes dry simultaneously. Pods with calyxes are at upper center, separated pods are on right, empty calyxes on left, and seeds at lower center. Photo November 30.

With regard to gardening, Hairy Bush Clover has an ungainly structure, non-showy leaves and flowers, and is not especially noticeable in winter months. Thus, it may be ideal only for a Wild Garden or Natural Area. Propagating by seed only, it is not an aggressive spreader. Branching can be encouraged by removal of stem tips at mid-season. Foliage is eaten by caterpillars of several Skipper species and the Io Moth. Seeds are eaten by birds and small mammals.

Photo 14: A volunteer plant in this Wild Garden has a dozen or so current-year stems, along with several dead stems that persist from the previous year. Plant at lower left is Arkansas Yucca. Photo – June 2.
Photo 15: Hairy Bush Clover is one of a number of plant species that hosts the Io Moth (Automeris io) caterpillar, noted for its sharp stinging hairs. Photo – September 20.

Frost flowers were seen on a dozen Hairy Bush Clover plants on January 3, 2022 in Logan County.
Temperature on that date was 23 degrees after an extended period of 70-degree weather and, two days
before, 3 inches of rain. Occurrence of Frost flowers on Hairy Bush Clover is unusual. One report can be found at the Biodiversity Heritage Library (biodiversitylibrary.org). For information on Frost Flowers, see “Frostweeds ‘Bloom’ Frost Flowers”.

Photo 16: Frost flowers on Hairy Bush Clover are unusual; requiring specific weather
conditions. Photo – January 3, 2022.

In Arkansas, 7 additional native species and 3 non-native species of bush clovers (Lespedeza) occur. Two of these are ground-hugging trailing plants and most of them have pink to lavender flowers. The one most similar to Hairy Bush Clover is Round Head Bush Clover (Lespedeza capitata). Round Head Bush Clover has similar structure and flower color, but its leaflets are linear-oblong, its inflorescence stalks are shorter than the leaf petioles, and its pubescence usually gives the plant a distinctly silvery appearance.

Article and photographs by ANPS member Sid Vogelpohl

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Know Your Natives – Fragrant Sumac

Fragrant Sumac (Rhus aromatica var. aromatica) of the Sumac (Anacardiaceae) family is a dioecious, low-growing, non-suckering, non-poisonous shrub with tiny yellow flowers that emerge before the leaves. The genus name Rhus is the old Greek and Latin name for sumac. The specific epithet is Latin for “aromatic” or “fragrant,” describing the strong and pleasant scent of the crushed leaves. In the U.S., Fragrant Sumac, at the broader species level, occurs across most of the country, but is generally absent from the Pacific Northwest, upper Midwest, Maine, and the Coastal Southeast. In Arkansas, the species occurs statewide except for portions of the Mississippi Alluvial Plain. Habitats are widely varied, the plants occurring on practically any soil type, dry to moist, with a preference for dry, sunny to partially shaded, rocky sites, such as woodland margins, prairie slopes, and rights-of-way.

Young plants have erect wiry stems, but in subsequent years, stems often become ground-hugging and wide-spreading. Those in contact with soil are anchored by shallow, fibrous roots, as well as by longer and deeper roots. Stems and their branches may be 12+ feet long with each stem having 1-4 ascending, smooth, brownish red branches that may be 3-5 feet long. Older stems become dull brown and roughened by elongate corky lenticels (air pores). A mature plant may have a dozen or more radiating main stems and hundreds of branches that form a dense thicket, especially when mixed with other shrubs and vines. When a larger stem is cut through, it visibly extrudes a sticky sap, containing concentrated tannin.

Photo 1: This 2-3-year-old erect plant is 12 inches tall. Photo – April 19.
Photo 2: Main photo (litter removed) shows “point of origin” for the stems of a plant that extend outward to 13 feet. Inset photo (soil and litter removed) shows roots and stems at the central rootstock of a smaller plant. Stems bear lenticels and roots have circular growth scars. Photos – September.
Photo 3: This plant is in a sunny rocky area has relatively short ascending branches and exhibits leaf loss due to drying conditions. Photo – August 1.
Photo 4: Display shows three stem segments at left and two branch segments at right. Branch segments, with leaves removed, grew in the current growth-year. Large stem is 5/8 inch wide at base. Photo – September 26.

The cone-like inflorescence appears in mid-summer at the ends of the current year’s floral twigs in axils of the uppermost leaves. The following spring (mid-March), twigs bear flowers and (in female or pistillate plants) immature fruits as the leaf-bearing branches appear. New branches are initially bright green (in mid-April) and elongate to a few inches or to as much as 3 feet. New leaves are puberulent on the upper surface, with longer hairs along the veins below––all lost by mid-summer. Floral twigs die by mid- to late summer, after fruits mature.

Photo 5: Current-year branches develop from axillary buds immediately below the floral/fruiting twigs. As seen, current year’s fruits are mature as next year’s floral twigs, with their cone-like inflorescences, are already present at branch apex. (Also see new branches in Photo 11) Photo – July 31.

Alternate trifoliate leaves, with a terminal leaflet and an opposite pair of smaller lateral leaflets, expand to 5 inches long (including a slender petiole to 1½ inches) and 4½ inches wide. Terminal leaflets tend to be obovate, lateral leaflets oval to elliptic and asymmetric. The terminal leaflet is strongly attenuate or wedge-shaped at the base and sessile to sub-sessile at its junction with the lateral leaf pair––a character that quickly separates Fragrant Sumac from look-alike Poison-Ivy and Poison Oak. Leaflet margins above the middle are coarsely toothed (crenate-serrate) with acute tips. Prominent pinnate venation is recessed above and expressed below. Leaflet blades, in age, are moderately thick and glabrous, medium green above and paler below; petioles tend to be reddish on the upper side. In the fall, leaf color changes to bright and decorative shades of orange and red.

Photo 6: Upper leaf surfaces are shown on left, lower surfaces on right. Note prominent pinnate venation, with the distal lateral veins terminating in the tips of the teeth, and sessile to sub-sessile terminal leaflets, a critical character that separates Fragrant Sumac from Poison-Ivy. Largest leaf is 4¾ inches by 4 inches. Photo September 17.

Like most (if not all) species of Rhus (as well as Toxicodendron), Fragrant Sumac is dioecious––staminate and pistillate flowers are usually borne on separate shrubs, although plants may occasionally bear some perfect flowers (polygamo-dioecious). Closely packed flowers bloom on short compact spikes (to 2½ inches long) on twigs that appeared the previous summer. Flowers are initially hidden behind tightly clasping, dark brown, rhombic bracts that have a thick apical fringe of short tannish hairs. Spherical buds extend out from behind the bracts. Flowers uniformly unfurl all-around the spike. At the time of bloom, in March, shrubs are leafless.

Photo 7: This shrub has many ascending stems with floral twigs at the tips. Height of stems is 3 feet. Photo – March 11.

The small, bright yellow flowers are bowl-shaped with 5 sepals and 5 petals, as well as 5 orange nectary discs at the base of the petals. The oval to elongate-triangular yellow sepals are brown at the tip. In full bloom, the petals extend well above the sepals. Sepals and petals join below to form a short and slim greenish base. Pistillate flowers have a single compound pistil, comprising a greenish, ovoid, pubescent ovary and 3 sub-sessile yellow styles with knob-like stigmas. Staminate flowers have 5 stamens between petals and nectary discs. The pale yellow filaments arch inward so that the dark yellow anthers are directed toward the flower center.

Photo 8: Stems and branches have lenticels whereas fertile twigs do not. As shown, the junction of the stem with the fertile twig (on right) was the base of a petiole. A Long-Horn Bee (Melissodes trinodis) collects nectar. Photo March 11.
Photo 9: These pistillate flowers each have a single compound pistil with three knob-like stigmas. An axillary leaf scar can be seen at twig-base. Flowers are ⅛ inch wide. Note orange nectary discs at base of flowers. Photo – March 13.
Photo 10:  Although the species is dioecious, these flowers have stamens as well as pistils (thus a perfect flower). Note brown-tipped sepals. (Note: Fruits were not produced.)  Photo – March 15.

Fertilized flowers develop spherical (3/16 inch wide) fruits that look spiky with their dense pubescence of straight red and white hairs. Fruits (drupes), with hard, smooth stones (⅛ inch long), ripen to bright red in May, when they are relished by birds and small mammals. If uneaten, they shrivel to a dark brown (in June). Fertile twigs often persist into the next fruiting season and may, at that time, still retain remnants of fruits.

Photo 11: Pubescent ovaries become pubescent fruits. These twigs and three new branches are growing from axillary buds on same stem. Photo- April 9.
Photo 12: Mature red drupes. Bracts along the spikes still remain firmly in place even after unfertilized flowers have dropped off. Photo – May 13.
Photo 13: With fruit maturity, twigs die, but may remain on the shrub well into the next year. Fruits each contain a single, ⅛-inch-long, smooth, oval stone. Photo – June 6.

Fragrant Sumac is well suited for a wild garden or natural area where its persistent, slowly spreading habit does not need to be restrained. It does well in many soil types including those that are drier and rocky. Even in partial shade, it can be a nice ground cover of medium height, producing early yellow flowers, reliable summer leaves, and bright fall color. Nectar attracts many insects and the fleshy fruits provide nourishment to birds and small mammals. (The fruits also make a tangy pink lemonade for people.) If needed, stems can be fairly easily removed by pulling and clipping. It is also good for erosion control, but it is browsed by deer.

Photo 14: Fragrant Sumac provides excellent fall color. Photo – October 28.

Four other sumacs are found in Arkansas: 1) Tall or Midwestern Fragrant Sumac (Rhus aromatica var. serotina), 2) Winged Sumac (Rhus copallinum), 3) Smooth Sumac (Rhus glabra), and Skunk-Bush Sumac (Rhus trilobata var. trilobata). Winged Sumac and Smooth Sumac are larger, rhizomatous shrubs with pinnately-compound leaves. Skunk-Bush Sumac is similar to Fragrant Sumac in its trifoliate leaves––and has been treated as a variety of Rhus aromatica (as var. flabelliformis) in the past. However, the leaves are much smaller, and this sumac is restricted in Arkansas to chalk glades and barrens in a small portion of Little River County in the southwestern corner of the state. Tall or Midwestern Sumac, another variety of Rhus aromatica, differs from the typical variety primarily in having taller stems, leaflets with more rounded apexes, and flowers that bloom after the leaves begin to grow in the spring. In Arkansas, it grows in calcareous sites in the Ozark Highlands in the north and in the southwestern corner in the state. (Fragrant Sumac is often found in more acidic sites.) Two other species of the family that are likely to also cause confusion are Poison Oak (Toxicodendron pubescens) and Poison Ivy (Toxicodendron radicans). For comparison of these two species with Fragrant Sumac, see “Leaves of Three, Let It Be. . . . Usually”.

Article and photographs by ANPS member Sid Vogelpohl

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Know Your Natives – Slender Mountain Mint

Slender Mountain Mint (Pycnanthemum tenuifolium) of the Mint (Lamiaceae/Labiatae) family is a rhizomatous plant with narrow, linear leaves that give the plant an attractive, airy appearance. The genus name is based on Greek words for “dense” and “flower.” The specific epithet is from the Latin for “slender leaved.” The species is widespread across the eastern U.S. from east Texas and southeastern Nebraska to Maine and northern Georgia, excluding most of southern Georgia and Florida. In Arkansas, occurrence is statewide except for limited areas near the Mississippi River. Habitats may be dry to wet and sunny to partially shaded, such as prairies, roadsides, and open woodlands. It is also known as Narrow-Leaf Mountain Mint.

Photo 1: The many, relatively small slender leaves give the plant an airy appearance. Photo – June 14.

This herbaceous perennial grows in clonal colonies from skinny, near-surface, branching rhizomes (underground stems). New rhizomes (1/16 inch in diameter) are white, smooth, and segmented (each segment ¼ to ½ inch long), with an opposite pair of tiny triangular brown bracts subtending the segments. Rhizomes develop long fibrous roots along their distal end and, in spring, the tips of these rhizomes become emergent as single stems. During summer months, multiple new rhizomes grow from near the end of the “old” rhizome. A dense root mat may develop, especially in loose mesic soils. Dead stems persist into the new year.

,tPhoto 2: Yellow arrow indicates the “old” brown rhizome, while white arrows indicate current-year stems. New rhizomes are white, the longest one 5½ inches. Inset shows a clonal root mat. Photo – September 11.
Photo 3: New stems emerge while previous year’s stems still persist. Stems and leaves are glabrous. Photo – March 19.

Erect, rigid, glabrous, typically reddish stems elongate to 2 to 3+ feet tall, with short branches in opposite decussate pairs along their upper half. Each branch is subtended by a leaf. A lateral branch does not rebranch unless the stem tip has been nipped. Branching continues to the stem apex which, for a flowering stem, terminates with a single flower head. The ascending branches (the lowermost to about 5 inches long) diverge from the stem at about 60⁰. Stems are slender––near the ground, ⅛ inch or less wide, becoming wiry and thread-like distally.

Photo 4: With stems beginning to branch along their upper portion, colonies are leafy with an airy appearance. Plant at lower left is False Aloe. Photo – April 2.

All leaves are simple and linear. Larger leaves may be 2 inches long and less than ¼ inch wide, widest at or just below mid-leaf. From mid-leaf, the long-tapering margins extend to a more or less sharp tip; a shorter taper extends to a blunt sessile base. Leaves have a slightly recessed upper midrib and an expressed lower midrib with an obscure pair of parallel secondary veins on each side. Leaves are glabrous. Margins are entire (smooth) and slightly revolute (downturned). They turn yellow in fall. Rubbed or even crushed leaves can be nearly scentless or with a mild minty scent caused by pulegone. Plants are usually much less aromatic than other members of the genus. Lower leaves are early deciduous.

Photo 5: The linear sessile leaves have parallel secondary venation, as best shown by the upper surface of the second leaf from left; that leaf is 1⅞ inch long and 3/16 wide).

Flowering occurs in June into July. Clusters of flower heads (¼ inch wide) at the tips of the main stem and uppermost branches form a broad inflorescence to 3 or more inches wide. Each head consists of 20 to 50 densely packed flowers. An opposite pair of small linear leaves (about 5/16 long and 1/16 wide) occurs immediately below the sessile head. Whitish linear bracts of unequal size, in 1 to 2 series, form an involucre subtending the heads. These elongate-triangular bracts, lighter green than the leaves, are loosely imbricate with long spiny-looking tips (but not prickly).

Photo 6: Single flower heads terminate the main stem and uppermost branches. The densely packed heads consist of 20 to 50 flowers. An involucre of bracts subtends the heads. Photo – June 8.
Photo 7: Individual flower heads terminate the main stem and opposite branch pairs. Heads are subtended by an opposite pair of leaves and an involucre of spiny-looking bracts. Photo – June 18.

Flowers bloom centrifugally, from the center outward. The tubular calyx (to ¼ inch long and 1/32 inch wide) is divided above into 5 ascending, triangular lobes. Relatively large tubular corollas are white to pale lavender with an unlobed upper lip and a 3-lobed, lavender-spotted lower lip. The upper lip and lobes of the lower lip are apically rounded, with lips widely spreading to expose the throat. Attached to the corolla tube are 4 slender white filaments with 2-lobed lavender anthers exserted above the corolla. After pollen release, anthers and filaments become shriveled and brown. From the base of the 4-lobed ovary, the slender white style, with a divided apex bearing the stigmatic surfaces, extends well beyond the stamens. Exterior of the corolla as well as its throat within bear a long twisty pubescence.

Photo 8: Flowers are positioned with the lower lips extended away from center of the head. As shown, most anthers have become brown and styles are divided (see at upper right). Photo – June 28.
Photo 9: Corollas have twisty pubescence on their exteriors and within the throats. Photo – June 12.
Photo 10: Three-lobed lower lips often have lavender spots. As shown, corollas have dropped from most calyxes. Photo – Jun 26.
Photo 11: Center head on left terminates a stem with the adjacent pair of heads terminating branches. The next lower branch pair has been cut to show underside of heads. Photo – September 12.

With fertilization, each flower produces 4 tiny (1/16 inch long), black, smooth nutlets that mature in September, while stems and leaves are still green. Dispersal of the 1-seeded nutlets may be by flowing water and strong wind. Heads persists on dead leafless stems into the next growing season.

Photo 12: Heads become brown while stems and leaves are still green. Fertilized flowers produce tiny smooth black nutlets. Squares are ¼ inch. Photo – September 4.
Photo 13: Fall foliage is yellow. Leafless stems and heads persist into the next growing season. Photo – November 7.

Slender Mountain Mints are a fine addition to a wild or native garden. They are interesting and decorative as well as ecologically beneficial for a wide variety of insects seeking nectar. The species is drought tolerant and deer resistant. Self-seeding seems to be minimal, however plants can be easily propagated by division. (In loosened garden soils, Slender Mountain Mint has the potential to form vigorous colonies that may be difficult to remove due to dense root-mats.) In its natural environment, colonies persist for many years.

Five other species of Mountain Mint occur in Arkansas: 1) White-Leaf Mountain Mint (Pycnanthemum albescens), 2) Short-Tooth or Clustered Mountain Mint (P. muticum), 3) Hairy Mountain Mint (P. pilosum), 4) Whorled Mountain Mint (P. verticillatum), and 5) Virginia Mountain Mint (P. viginianum). Of these, Whorled Mountain Mint and Virginia Mountain Mint (both state species of conservation concern) are most similar to Slender Mountain Mint due to their narrow leaves. Slender Mountain Mint can be distinguished by its linear leaves less than ¼ inch wide and by its glabrous leaves and stems. Natural hybridization has been documented among native Mountain Mints, though, so difficult-to-identify plants may occasionally be encountered.

Article and photographs by ANPS member Sid Vogelpohl

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Know Your Natives – Downy Ragged Goldenrod

Downy Ragged Goldenrod* (Solidago petiolaris**) of the Aster, Sunflower, or Composite (Asteraceae) family has stiff lanceolate leaves on unbranched stems that are topped by an unusually large array of golden-yellow flower heads. The genus name is based on the Latin solidus, meaning “whole,” in reference to purported health benefits of some species. The specific epithet is from the Latin for “with petiole.” In the U.S., the species occurs primarily from southern Nebraska and Texas, east to the Carolinas and northern Florida. In Arkansas, it occurs statewide except for portions of the Mississippi Alluvial Plain and Crowley’s Ridge. Preferred habitats include more or less sunny, mesic to dry, sandy to rocky areas, such as open woodlands, glades, and blufftops. It is also known as Woodland Goldenrod.

This herbaceous perennial develops a central rootstock of weakly connected segments with numerous fibrous roots. Each knobby segment bears one to several stems. Buds for the next year’s stems develop at the base of the current year’s stems. Dead stems persist into the new growth-year. Erect, fleshy springtime stems tend to be pubescent and reddish, while mature stems become reddish brown to brown below as they stiffen. Stem growth above in the inflorescence tends to be bright green before also becoming reddish to brown.

Photo 1: This rootstock, composed of five weakly connected segments and numerous fibrous roots, bears a dozen living stems while retaining dead stems. Round scars (at front) are remnants of three-year-old stems. Buds for next year’s stems can be seen at far right. Photo – August 20.

Stems, with slight longitudinal ridges, grow to unequal heights, often reaching 4+ feet tall and, at base, 3/16 inch in diameter. They are unbranched unless the growing tip has been damaged. Lower portion of stems typically loses leaves by mid-growth-year, becoming smooth except for projecting petiole bases. Depending on the site, they may be erect, ascending or sprawled.

Photo 2: Springtime leaves and stems bear short pubescence, becoming glabrate as plants mature, except for leaf margins. Photo – April 8.

Plants have alternate, simple stem leaves, narrowly elliptic, spreading to ascending, and stiff, at midstem to 4 inches long and ½ inch wide, gradually decreasing to as little as ⅛ inch long in the terminal inflorescence. They are sessile to short-petiolate, with margins entire (smooth) to shallowly serrate distally, the teeth mucronate. Upper leaf surface is green with a satin sheen, the lower surface with a dull sheen. Venation is pinnate with a single strong midvein and secondary veins that curve forward to parallel the margins. Mature leaves feel slightly rough from microscopic hispid pubescence, with hairs more prominent on the main veins beneath. Margins are ciliate with the hairs angled toward the apex. As soil dries during summer, leaf-drop proceeds up-stem.

Photo 3: Stems have closely spaced narrowly elliptic, simple leaves that extend from stem base into the inflorescence. Dead stems persist into the new growth year. Photo – March 4.
Photo 4: Upper surface of a 2½ inch leaf shown above, the lower surface below. Ciliate pubescence of upper leaf can be better seen in its shadow. Secondary veins curve and parallel the margins. Tertiary veins are reticulate. Photo – August 28.
Photo 5: Set of three leaves at top, left and right are from different plants. Left leaves are serrate while top and right leaves are entire. Margins are narrowly downturned, as can be seen on lower left leaf. The lower stem segment is 3⅛ inches long and 3/16 inch wide. Pubescence is not visible on leaves or stem. Photo – August 31.

Composite flower heads, with ray and disk florets, bloom in September and October. The axillary inflorescence, along the upper portion of the stem, consists of individual flower heads and tightly branching clusters of 3 to 7 flower heads, forming columnar or spikelike panicles. An inflorescence may be 4 to 10 inches long with up to 150+ heads, the flowering proceeding from apex to base. Individual heads or clusters are subtended by a small leaflike bract. While pedicels of single flower heads are consistently short, peduncles of clusters may be a bit longer (to ½+ inch). When plants are erect, flower heads are arranged equally around the stem; when sprawled, heads twist toward sunlight so that the inflorescence is secund (heads all on upper side). Pedicels and peduncles bear closely spaced linear-oblong bracts that transition to the linear-lanceolate phyllaries of the involucre (to ¼ inch long). Heads are about ¼ inch long and ⅛+ inch wide. Pedicels, peduncles, bracts, and phyllaries are light green with short hooked pubescence, that of the phyllaries being glandular.

Photo 6: Developing inflorescence of two stems at left consists of individual flower heads. Tip of stem at right was apparently damaged, so that lateral branches developed. Stem leaves may continue into the inflorescence (right stem) or transition to bracts (left stems). Photo – August 26.
Photo 7: Flowerheads on spreading to sprawled stems twist sunward so that the inflorescence is secund, but leaves remain arrayed about the stem. Plant at lower right is Goat’s Rue. Shrubs are Sparkleberry. Photo – October 25.
Photo 8: Flowers of this inflorescence (a panicle) are in tightly branched clusters, the distal heads blooming first. Blooming sequence of inflorescences begins at the apex. Photo – September 7.

The golden yellow flower heads comprise 5-10 pistillate (with pistils only) ray florets that surround 8-18 perfect (with pistils and stamens) disk florets subtended by an elongate cuplike involucre. The involucral bracts (termed phyllaries in the composites) are disposed in 3-4 series, with spreading to sharply recurved, triangular tips that give the heads a bristly appearance. Inner and outer surface of phyllaries bear minute glandular pubescence which may cause them to feel viscid. Heads bloom centripetally, from the ray florets inward to the center. Ray florets have a single linear to oblong ligule (the exposed portion of the corolla), ¼+ inch long, that has several longitudinal pleats, a rounded apex and tapered base.

Disk florets have tubular corollas, 5 stamens (filaments + anthers) and 1 pistil (ovary + style + stigma). The corollas, about 3/16 inch long, are topped with five narrow, erect, triangular lobes. Anthers of the free staminal filaments are fused together into a ring surrounding the style. As the style elongates through the anther ring, it carries the pollen above the corolla, where it is available to be dispersed by pollinators. With pollen released, anthers wither and the exserted style narrowly bifurcates to expose linear stigmatic surfaces for pollen capture. Corollas of disk florets are surrounded by a pappus of straight hairs, attached to the summit of the inferior ovary.

Photo 9: Clusters of flower heads seen from below and above. Pedicels and peduncles bear bracts that transition to the overlapping phyllaries. Bifurcated styles of two ray flowers can be seen in lowermost flower head. A number of slightly bifurcated styles of disk florets can also be seen. Photo – October 3.
Photo 10: Flower head shows: 1) flowering sequence moving from ray florets toward center of head, 2) 5 lobes of the tubular disk florets, 3) raised margin of disk corolla lobes, 4) slender filaments and anther rings, and 5) extruded pollen (far right). Elsewhere: 1) hooked ciliate pubescence on leaf (lower left) and 2) glandular pubescence on recurved phyllaries (upper left). Photo – October 18.

Fertilized ray and disk florets produce flattened elongate achenes (referred to as cypselae in Aster family) topped by pappus. The ⅛ inch long achenes are longitudinally ribbed. Dry pappus radiates from the apex of the achene where it provides lift for wind dispersal.

Photo 11: As flower heads dry, the enlarging ovaries/cypselae bulge upward as the exposed pappus dries and radiates from summit of the elongate cypselae. Photo – November 11.

Downy Ragged Goldenrod, with its large and decorative, late-summer and fall inflorescence, is an excellent choice for a wildflower garden. As with other goldenrods, its flowers provide nectar and pollen for a wide variety of insects, and seeds are consumed by small song birds. The long graceful stems can be somewhat “disorganized” so that staking may be needed. Plants do not spread by rhizomes. When soil dries, this species seems to be more prone to leaf drop.

Downy Ragged Goldenrod is one of some 30 or more species, subspecies, and varieties in the Solidago genus recognized in Arkansas. Of all these species, it most closely resembles Buckley’s Goldenrod (Solidago buckleyi) which has a similar inflorescence and spreading to recurved phyllaries. Buckley’s Goldenrod has fewer and significantly larger and thinner leaves that consistently have prominent marginal teeth.

*“Downy” may be a reference to early pubescence of stems and leaves which is mostly lost with plant maturity. “Ragged” may be based on the plant’s overall appearance at bloom-time: its long unbranched stems of varying lengths; its firmly positioned, often sprawling and twisty stems; and leaves that drop as available moisture declines.

** Leaf and phyllary shape and pubescence are variable across its range. Some authorities recognize varieties that are not addressed here. Arkansas plants are in need of further study.

Article and photographs by ANPS member Sid Vogelpohl

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Know Your Natives – Late Boneset

Late Boneset (Eupatorium serotinum) of the Aster, Sunflower, or Composite (Asteraceae) family is a tall herbaceous perennial with small, clustered, whitish flowerheads that lack ray florets. The genus name recognizes Mithridates Eupator who invented a “universal antidote” against poisoning and is said to have used a species of the genus in medicine. The specific epithet translates as “developing late” in reference to the time of flowering. The species is wide-ranging, from the Big Bend area of Texas to Illinois, east to the Atlantic and Gulf Coasts, and including most of Florida. In Arkansas, it occurs statewide. The common name “boneset” originates from past use of some species of the genus to relieve pain. Plants are common in a variety of open to partly shaded habitats––prairies, woodlands, rights-of-way, roadsides and fallow fields––on mesic to dry soils.

Young single-stem plants have a stubby central rootstock with long near-surface spreading fibrous roots. At the end of the growing year, stems die with new stems developing the following spring from bases of the old stems. Over time, this short-lived perennial develops a gnarly central rootstock supported by a mass of wide-spreading fibrous to ropy light-tan roots. As new stems develop, the older central portion of the rootstock decays.

Photo 1: New stems grow from base of dead stems as the central portion of the rootstock decays. Width of that portion of the root mat shown is 7 inches. Photo – August 14.

Plants, lacking basal leaves, have one to several stems that may be 2-6+ feet tall, those in mesic soils being taller. Early in the growing season, stems tend to be purple, but later become medium green with faint, reddish ridges. Main stems are straight and erect, with their upper half to two-thirds bearing opposite pairs of spreading to ascending, axillary (primary) branches that decrease distally in length. More robust plants branch more profusely. All branches typically terminate in an inflorescence. Near the branch tips, leaves and branches may become sub-opposite or even alternate. Stems and branches are uniformly puberulent.

Photo 2: As an herbaceous perennial, new spring growth originates directly from the rootstock. Plants do not have basal leaves. Photo – March 28.
Photo 3: Leaves are in matched decussate pairs, except that those near the tips of branches may be sub-opposite or even alternate. Photo – May 10.
Photo 4: Stems are erect throughout the growth-year. As shown, branches have begun to grow along the stem’s upper portions. Stems, early in the growth year, are a solid purple. Photo – June 3.

Leaves are decussate, petiolate, and broadly lanceolate to lanceolate, becoming narrower above. A typical larger lower stem leaf may be 9½ inches long (including a 2½-inch petiole) and 2½ inches wide. An upper leaf, at the base of the inflorescence, may be 1⅝ inches long (including a ¼-inch petiole) and ¼ inch wide, while the uppermost leaves (subtending the final floral branches) become tiny and almost linear. Margins of larger leaves are boldly serrate while those of smaller leaves become entire. Margins taper gently to acute apexes. Upper leaf surface is glabrous, lower surface and underside of petioles puberulent. Upper surface is a shiny green, lower surface a dull pale green with the main veins yellowish green. Venation, recessed above and expressed below, is longitudinal with 2-4 secondary veins parallel to the midrib. Petioles are swollen and clasping at the base. Lower stem leaves that do not subtend a branch, tend to subtend a rudimentary branch or tuft of leaves. With drying conditions, lower leaves drop off.

Photo 5: Paired decussate branches are subtended by paired decussate leaves. Note stem puberulence and somewhat clasping bases of petioles. Photo – July 12.
Photo 6: Lower stem leaves, mid-stem leaves, and upper-branch leaves, the upper surfaces shown on left, lower surfaces on right. Larger blades are widest just above base. Venation is longitudinal. Leaf at left is 7¼ inches long, including a 1⅞ inch petiole.

Plants flower from mid-August into October. Spreading clusters of small flowerheads arranged in corymbs at the branch tips produce a broad, flat-topped inflorescence. Corymbs, with 6-10 closely spaced flowerheads, bloom outward from the base. Each head comprises 8-15 disk florets; ray florets are absent. Inflorescence branches, peduncles and pedicels are clothed in a fine white puberulence.

Photo 7: Display of parts of a 5½ foot stem. The ¾-inch-diameter stem at left, lower leaves having dropped off, was at ground level. Paired branching (lower right) is consistently repeated into the inflorescence (upper center). Photo – August 8.
Photo 8: The overall inflorescence tends to be flat-topped. The inflorescence is an insect magnet and provides a hunting ground for this White Banded Crab Spider (Misumenoides formosipes). Photo – September 24.
Photo 9: Terminal clusters are composed of several corymbs, each having 6-10 flowerheads, each composed of 8-15 disk florets. All parts of the inflorescence below the corolla are densely puberulent. Photo – September 6.

Disk florets, with whitish, 5-lobed, tubular corollas, are set in a cylindrical involucre of up to a dozen imbricate, elliptical phyllaries, about ⅛ inch long, in 1-2 series. Purplish stamens remain hidden within the corolla throat. The white style pushes upward through the ring of fused anthers, at first displaying the pollen, and ultimately dividing and spreading to receive pollen from other florets.

Photo 10: Disk florets, with white, 5-lobed, tubular corollas, are packed in a cylindrical involucre. Stamens and bristly pappus are hidden at this stage of floral development. The divided style arms extend well beyond the corollas. Photo – September 6.

After fertilization, corolla, stamens and style are shed from the inferior ovary as the pappus of 20+ white hairs or bristles dries and radiates from its apex. Ovaries mature into dark brown, cylindrical, slightly ribbed achenes, less than 1/16 inch long, dispersed by wind.

Photo 11: As the stem dies, the pappus radiates from the top of the achenes, providing lift and wind dispersal. Photo – November 13.

In considering Late Boneset for a garden, there is a good chance that volunteer plants are already there. Multiple plants may create a weedy appearance, but individual plants can be attractive as specimens, especially where associated with other native plants of differing texture, structure and color. Bonesets, mostly avoided by deer, are attractive to many insects. Removal of the dying stems from this short-lived perennial before seed dispersal would help control self-seeding.

Photo 12: In this garden setting Late Boneset grows with False Aloe, Dittany, Rose Vervain, Hairy Blazing Star, and Hairy Skullcap. Photo – July 18.

Late Boneset is one of some 20 species and recognized hybrids in the genus Eupatorium that occur in Arkansas. Many of these other species have white flower heads that are similar to those of Late Boneset. The leaf characteristics of Late Boneset––the undivided blades, long petioles and marginal serrations––separate it from most of those other species.

Article and photographs by ANPS member Sid Vogelpohl

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