Know Your Natives – Royal Fern

Royal fern (Osmunda regalis var. spectabilis*) of the Royal Fern (Osmundaceae) family is a large herbaceous fern with a crown of clustered spore cases (sporangia) on the fertile fronds (leaves). In the U.S., it occurs from eastern Texas to Minnesota and thence to the Atlantic and Gulf Coasts. In Arkansas, it occurs pretty much statewide. The genus name, according to some writers, originates from “Osmunder,” a Saxon name for Thor, the god of thunder. The specific epithet is from the Latin for “regal” or “royal,” in reference to the fern’s size and majestic appearance. The variety name is from Latin for “admirable” and “spectacular”. It is also known as regal fern and American royal fern (this being the only variety in North America). Habitat preference is partly to mostly sunny areas with consistently wet to occasionally flooded soils, such as shallow, slow-moving drainages, bogs, marshes, seeps, moist bluffs, and open wetlands.

Royal fern has a stout, elongate rootstock that may be oriented vertically (in less-wet habitats) or horizontally (in wetter habitats). Dense, black, wiry and tough fibrous roots completely shroud the rootstock. New fronds (leaves) emerge at rootstock’s apex, surrounded by stubs of previous years’ leaves. Apices of vertically positioned rootstocks may become elevated above duff level while apices of horizontally oriented rootstocks remain at duff level, in rhizome-like fashion.

Photo 1: This 2½ foot-tall plant has matted fibrous roots which enshroud a horizontally oriented rootstock that is 9½ inches long and 1¾ inches wide.

In early spring, new fronds appear as large fiddleheads which unfurl into smaller fiddleheads that unfurl into pinnae (leaflets). The large fiddleheads are initially covered with long, matted pubescence which drops off as the stipe (leaf stalk) and rachis (midrib) elongate. Unfurled leaves are bipinnate or twice-cut into pinnae (leaflets) and pinnules (secondary leaflets). Depending on the habitat and season, fronds may be erect, ascending or arching. Fronds gradually decline in the fall and, except for frond stubs, disappear over winter.

Photo 2: In early April, newly emergent fiddleheads are temporarily covered with matted pubescence.
Photo 3: Fiddleheads remain mostly closed as stipes elongate to several feet tall. Fern at lower right is lady fern (Athyrium filix-femina).

Fronds are typically 2 to 4 feet long (maximum about 6 feet) and about half as wide, with widely spaced, opposite pinnae that elongate to 12 inches. Fronds are sterile or fertile, both having the same vegetative structure. However the upper pinnae and pinnules of fertile fronds lack chlorophyll and are modified into clusters of spore-producing sporangia. Below the sporangia, fertile fronds have the same appearance as sterile fronds. 

Photo 4: Sporangia of plants on left are green while those of plants on right have become brown after release of spores. Lady fern (Athyrium filix-femina) at lower right and Christmas fern (Polystichum acrostichoides) at lower left.

Pinnae of both sterile and fertile fronds bear six to twelve pinnules to 2 inches long and ⅜ inch wide. Pinnules are alternate to offset-opposite, mostly oblong, with rounded apexes and rounded to truncate-oblique bases. Margins are slightly undulating and minutely serrate. Fertile pinnae are greatly reduced in size. Spherical sporangia, maturing from frond apex downward, occur in small, naked, short-stalked clusters. Initially dark green, due to the chlorophyll-bearing spores within, sporangia turn lighter green to golden brown as they mature and then split in half across the top to release the spores. Sporangia then wither, and in late spring, the entire upper spore-bearing portion of the fertile fronds quickly shrivels. The lower portion of fertile fronds remains green and photosynthetic.

Photo 5: An 18-inch long section of a 4-foot long fertile frond. Fertile (sporangium-bearing) pinnae are significantly smaller than sterile, photosynthetic pinnae.
Photo 6: Clusters of sporangia replace leafy pinnules at tips of fertile fronds. Sporangia split across their tops for spore dispersal.

With spores dispersed, the reproductive activity of the “sporophyte phase” of the fern’s life cycle concludes. In the soil, spores germinate to produce a prothallus, the “gametophyte phase.” The tiny, ephemeral prothallus produces not spores but gametes, sperm and egg. Mobile sperm swim through ground moisture to fertilize eggs that have remained attached to their prothallus. Fertilization then produces a zygote that in turn develops into a large, perennial sporophyte plant. Readers who have taken a general botany course may remember this complex, elaborate life cycle being described as an “alternation of generations.”

Royal fern would be an excellent choice for mesic (in shade) to hydric (in sun) areas of a native plant or fern garden. Like most temperate zone ferns, it is herbaceous, dying to the ground each winter. But from spring to fall, with its large, bold structure, yet elegant and graceful fronds, it is a striking addition to the garden, either as a single plant or as a colony.

Photo 7: In fall, fronds recline and become more yellowish. Photo–October 23.

In addition to royal fern, two other members of the Osmundaceae family occur in Arkansas: interrupted fern (Osmunda claytoniana) and cinnamon fern (Osmundastrum cinnamomeum). While royal fern has bipinnate leaves (pinnae fully divided into pinnules), the other two ferns have pinnate-pinnatifid leaves (pinnae deeply lobed but not fully divided). Also, sporangia of interrupted fern, unlike those of royal fern, are located on fertile pinnae below the apex of fertile fronds (about mid-frond, with sterile pinnae above and below). Cinnamon fern has entirely separate fertile fronds that bear sporangia only.

*Recent genetic studies suggest that the royal fern of North America is a separate species (Osmunda spectabilis), but this reclassification has not been fully accepted by the botanical community.

Article and photographs by ANPS member Sid Vogelpohl

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Know Your Natives – Climbing Rose

Flowers of climbing rose (Rosa setigera) of the Rose (Rosaceae) family, one of four native roses that occur in Arkansas, have a single layer of five pink (occasionally white) petals. The genus name is Latin for “rose,” the specific epithet, also Latin, means “bristle-bearing”. Climbing rose occurs in the U.S. from Texas to Wisconsin east to New Hampshire and the Atlantic and Gulf states. In Arkansas, it occurs in the northwestern three-fourths of the state. Another common name is prairie rose. Preferred habitat is fertile, dry-mesic to mesic soils, in partial to full sun along streams, woodland borders, fence rows, rights-of-way, and in prairie thickets.

Climbing rose produces long slender trailing or climbing arching stems and branches, along with fast-growing suckers that arise off the rootstock or off main stems. When supported by other vegetation or structures, plants may reach 15 feet tall. In open areas, stems arch so that mounds to 3 feet tall may form. When growing tips of branches touch the ground, roots emerge and a clonal plant is established. Stems and branches that extend along the ground without touching soil do not develop roots. New stems and branches, typically glabrous, are a light green the first year, later becoming light brown and woody.

Photo 1: In this fence row, competing for sunlight, climbing rose has support from surrounding vegetation.

Stems and branches of climbing rose have thick prickles which easily break off the epidermis when side-pressure is applied. Smaller diameter stems may have pairs of prickles just below leaf nodes. Larger diameter stems have a few to many additional prickles scattered along the internodes. The stout, down-turned prickles, to ⅜ inch long, have broad flattened bases (to ¼ inch) set parallel to the stem. Prickles, tapering to a very sharp hard point, hold stems and branches in place and provide some protection from herbivores.

Photo 2: Prickles on this vigorous sucker-stem are especially stout and numerous. Prickles are persistent on dead woody stems. Note stipules fused to the lower portion of the leaf petiole

Deciduous, odd-pinnately compound leaves, to 2 to 4 inches long and 2 to 3 inches wide, have three to five leaflets (one terminal leaflet and one or two pairs of laterals). Three-leaflet leaves tend to occur near the inflorescence, five-leaflet leaves away from the inflorescence and on more vigorous stems. Petioles (leaf stalks below lowermost leaflets) have a widened clasping base and lateral wing-like stipules that distally terminate with an acute out-flared ear-like tip (auricle). Margins of stipules are entire to finely toothed. Lateral leaflets have 1/16-inch-long petiolules (leaflet stalks); those of terminal leaflets may be ½ inch long. Abaxial (lower) surface of the petiole, rachis (midrib), and terminal petiolule bears stout to nearly invisible down-curved pricklets, along with stubby knobbed glandular hairs (stipitate-glandular pubescence).

Leaves have leaflets that are ovate to elliptic with rounded bases and acuminate apexes. Pinnate venation is conspicuous. Adaxially (above), leaflets appear rugose, the veins recessed below the blade surface. Leaflets are mostly glabrous, though fine pubescence may be present along abaxial veins. Revolute margins are serrate. 

Photo 3: Stem on left grew the current year (leaves removed) while stem on right (branches removed) grew the previous year. Note leaf coloration, extent of serrate margins, venation, and stipules adnate (fused) to petiole, forming narrow wings.

Inflorescences develop in mid-spring and consist of single or compound clusters of flowers that terminate new-growth stems and branches. A branch with a single cluster may have several to a half-dozen flowers. Larger stems may have up to 36 flowers on a half dozen floral branches further divided into secondary branches. A flower cluster on a secondary branch typically has three flowers, a terminal flower and two laterals with pedicels connecting at a common point. Central flowers of individual clusters are the first to bloom followed by those below. Flowering persists for several weeks to a month. Floral branches are subtended by smaller three-leaflet leaves. Within secondary floral branches, flowers are subtended by one to three lanceolate, half-inch-long bracts.

Photo 4: Stipitate pubescence extends from sepals to pedicels. If a pedicel has a node (see black arrows), pubescence stops at that point.

Flower buds are round in cross-section, with a constricted base, wide lower section and acutely pointed tip. Buds are protected by five narrowly triangular sepals that may have a few randomly-placed narrow lobes along their otherwise entire margins. Outer surface of sepals is stipitate-glandular as well as short tomentose. With anthesis, sepals become reflexed (falling off with fruiting).

Flowers are beautiful: 2½ to 3 inches wide, with five light to medium pink (fading to white) petals that typically overlap slightly in their lower half. Although scented, the flowers do not have the pleasant scent associated with most roses. (Occasionally, petals are white instead of pink.) The conspicuous androecium comprises numerous stamens with pale yellow filaments tipped by golden yellow anthers. (In the typical horticultural rose, most of the stamens are genetically converted to petals to create the double-multiple form.)

About 20 pistils are present. Their ovaries are sunken into the tissue of the receptacle (the stem tip), which forms an enclosing structure around them called a hypanthium. The styles form a tight column that emerges from the hypanthium at the center of the dense ring of stamens. Stamens, petals and sepals are attached to the summit of the hypanthium, sometimes called the hypanthial disc. The mature hypanthium with its enclosed seeds becomes a unique fruit: the rose hip.

Photo 5: The column of styles, surrounded by numerous stamens, emerges from the hypanthium through the hypanthial disc. Broad gently wide-notched petals have a central tip. Photo – May 29.
Photo 6: With petals removed, display shows 1) dissected pedicel, 2) sepals, 3) stigmas grouped at top of style column, 3a) style column, 3b) styles emerging from hypanthium, 3c) ovaries, 4) stamens, 5) hypanthium, and 5a) hypanthial disc. Note dry fibrous hairs within hypanthium.

Pistils that are fertilized mature into achenes (indehiscent, one-seeded fruits) within the developing hypanthium or hip, which becomes red and fleshy in late fall. The spherical, berry-like hip, ⅓ inch in diameter, retains the stipitate glands that were present even at flower bud stage and bears a scar of the hypanthial disc at its tip. Hips are eaten by various mammals and birds, thus effecting dispersal.

Photo 7: Display of leaves, hips and achenes. Photo – November 21.

In a native plant garden, this climber would need regular training and trimming. It would do well inter-planted with various other native vines and shrubs where a screening effect is desired.

In addition to climbing rose, at least nine other rose species have been documented in the wild in Arkansas, of which three are native: Carolina rose (Rosa carolina), white prairie rose (Rosa foliolosa), and swamp rose (Rosa palustris). Of these three, Carolina rose and swamp rose have consistently pink flowers. Climbing rose can be distinguished by its climbing nature and rooting of branch tips. A non-native climber, multiflora rose (Rosa multiflora) has smaller white to light pink flowers and comb-like (fimbriate) hairs on its stipules.

Article and photographs by ANPS member Sid Vogelpohl

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Know Your Natives – American Snowbell

American snowbell or storax (Styrax americanus) of the Storax (Styracaceae) family is a large deciduous shrub with bell-shaped snowy-white flowers. The genus name is the ancient Greek name for a European species, Styrax officinalis. The specific epithet refers to the native range of the species. In the U.S., it occurs from Illinois and Virginia south to the Atlantic and Gulf Coasts. In Arkansas, it is found across the state except for the Highlands of the northwestern one-third of the state. An understory species in nature, it prefers hydric soils in and along borders of swamps, boggy areas and drainages. In its natural semi-shaded habitat, it is a broad shrub with an open structure.

A deciduous, non-suckering, multi-stemmed shrub with thin, smooth, finely textured bark, storax grows to about 15 feet. Older stems are finely mottled in gray and pale green while previous year’s twigs are finely lined in tans and browns. Twigs of new growth are light to medium green.

Photo 1: American snowbell is an understory shrub that favors wet soils. Main stems tend to be straight and ascending. Photo – May 12.
Photo 2: Main stems join near ground level. Bark is thin and smooth.

New twigs grow from terminal and lateral buds (buds are without protective scales) along previous year’s twigs. New twigs are covered with very short and dense woolly pubescence. The terminal bud and several distal lateral buds develop vigorous new leafy twigs with no or few terminal flowers. Lateral buds occur in pairs, one above the other. Proximal buds develop into less dominant leafy twigs that bear one to several individual flowers in leaf axils. While distal twigs may be 6 inches long, proximal twigs are shorter, to 3 inches long. These tend to die out within a year or two so that the interior of a shrub tends to be open. Twigs are slightly zigzagged.

Leaves are elliptic to oval with larger elliptic leaves occurring toward the twig apex and smaller oval leaves occurring toward the twig base. Large leaves may be 3 inches long, including a ⅛- to ¼-inch-long petiole, and 1½ inches wide. Small leaves, to as small as ¼ inch long, have the same proportions, with petioles remaining about ⅛ inch long. Pubescence of twigs decreases onto petioles and underside of leaf blades. New leaves have a medium green upper surface that darkens with age. The lower surface is paler.

Venation is prominent, with four to six widely spaced, off-set lateral veins. Secondary veins arch toward blade margins, but blend with tertiary veins a short distance from margins. Upper veins are recessed, lower veins expressed.  Tertiary veins form a reticulate pattern. Leaf margins are distinctive, bearing tiny soft-tipped teeth.

Photo 3: The divide between current-year twig and previous-year twig is indicated by the red arrow, the site of the previous year’s terminal bud. Inflorescences are borne on lateral twigs growing from lateral buds along previous year’s twig. Upper side of twigs shown.

Pendulous, bell-shaped (campanulate) flowers, blooming in May, are evenly distributed around the shrub, with flower-density greater in brighter light. Most flowers grow from leaf axils (axillary) sited along new lateral twigs, one or two flowers per leaf. Additionally, racemes of two to five flowers grow directly from the tip of lateral twigs (terminal flowers).

Photo 4: Underside of same twigs shown in Photo 3. Leaf axils of lateral twigs bear one or two individual flowers, while short racemes of flowers terminate the same twigs. Note differences in leaf color and venation between this photo and Photo 3.

Flowers are showy, and the shrubs are often used ornamentally. The corolla is sympetalous, with 5 snowy-white, recurved lobes, measuring about ¼ inch broad. The 8-10 white stamens form a compact group around the pistil. The slender white style extends just beyond the stamens. Stamens are free-standing in their upper two-thirds and fused to one another at their base. The ring of stamens is also fused to the base of the corolla tube. Anthers are elongate and vertically aligned with the filaments. They dehisce on their inward side to release yellow pollen. The style is tipped with a slightly green flat stigma. The corolla tube is set in a short, cuplike calyx rimmed with five short teeth.  Ovaries are superior. With the passing of anthesis, the corolla, with the stamen group intact, separates from the calyx, exposing the ovary. Pedicels are about ¼ inch long.

Photo 5: Display shows: #1) a flower bud (over-draped by a discarded corolla), #2) flowers at anthesis, #3) corolla and stamens separating from calyx, and #4) ovary within a calyx, with style still attached.

In mid- to late September, fertilized flowers produce globose, ¼-inch-long drupes that each contain a single nutlet surrounded by a thin but tough shell. Fruits are secured by pedicel and calyx until maturity. Exterior of fruit, calyx and pedicel are light yellowish green with a fine dense pubescence. As fruit develops, the shell splits along three lines from the base, while remaining connected at the tip. At maturity, the shell  becomes yellowish tan, ultimately opening fully and releasing a dark brown, hard globose nutlet.

Photo 6: Twig with leaves and fruit, the fruit before dehiscence held by the calyx and pedicel. Open fruit: shell dehisced from base to apex and globose nutlet fallen out.

American snowbell would be attractive in a garden or natural area with consistently wet soil and sufficient space for a large shrub. It can do well in a partially to fully sunny site. Sunnier sites will produce a denser shrub that has a greater floral display.

Big-leaf snowbell (Styrax grandifolius), a shrub to small tree, also occurs in Arkansas. American snowbell can be distinguished from big-leaf snowbell by its preference for hydric sites, its smaller, more-elliptic leaves, and fewer flowers per terminal raceme.

Article and photographs by ANPS member Sid Vogelpohl

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Know Your Natives – Aniseroot

Aniseroot (Osmorhiza longistylis) of the Carrot (Apiaceae) family is a herbaceous erect perennial that has pleasantly aromatic roots. It occurs across most of the U.S. from New Mexico to Montana, thence east to the Gulf and Atlantic Coasts, with the exception of Louisiana and Florida. In Arkansas, the species occurs in the Highlands of the northwestern half of the state and on Crowley’s Ridge. The genus name is from Greek words for “aromatic root”. The specific epithet is from Latin for “long-styled”. Other common names include sweet anise, long-style sweet-cicely, and smooth sweet-cicely*. It occurs in moist deciduous woodlands with light to moderate shade in soils enriched with decaying plant material.

Plants have thick, branching tap roots that terminate in long fibrous roots. Crushed roots have an anise scent.

In spring, new buds sprouting from the caudex (stem base) develop into basal leaves and a compressed mass of developing stems, leaves and inflorescences. Fully developed basal and cauline leaves have three pinnate leaflets that may be further pinnately divided into sub-leaflets (ternately pinnate to bipinnate). At the end of the growing season, stems decay while basal leaves may become ground-hugging and persist into spring.

Photo 1: In this early January photo of branching taproots, previous year’s basal leaves persist (extending off top of photo) and buds for new growth can be seen on caudex.
Photo 2: In this early April photo, a mass of developing stems, leaves and inflorescences emerge at center of plant. The large basal leaves are bipinnately compound, as are cauline leaves that will develop later.

Above the basal leaves, mature plants have one or two erect, typically pilose (densely short-pubescent), solid stems that grow to a height of about 2½ feet. Nodes are rather swollen and bear single cauline leaves which may subtend lateral or floral branches. Stems are a light green with lower portions and areas near nodes sometimes purplish. 

Photo 3: Immature ternately bipinnate leaf has a clasping base from which a compound umbel (with white flowers) has grown along with a lateral branch that bears another developing umbel (hanging down). Photo – April 15.

The compound leaves, to about 9 inches long and 12 inches wide, are divided into three principal sections (ternately compound). Leaflets have thin, rather flimsy blades with prominent irregularly wavy (sinuate) margins. They are a dull light to medium green on both surfaces. Stalks of leaves and leaflets are rounded on their upper side and flattened and grooved beneath. Crushed leaves have a light anise scent. 

Photo 4: This plant has two ascending basal leaves and two well-developed, cauline leaves, of which the uppermost subtends a peduncle with white flowers in a compound umbel. Note fine pubescence along purplish stem.

Inflorescences, flowering in mid-spring, are terminal and axillary compound umbels, consisting of one or two slender peduncles about 2 inches long. These terminate in three to six rays, each tipped by 5 to 17 pedicels supporting the umbellets of flowers. Rays are subtended by an involucre of 1-6 bracts, the umbellets by an involucel of 4-6 bractlets. Umbellets bear about 5-17 flowers, of which 5-7 are perfect (having both pistils and stamens), typically arranged around the perimeter of the umbellet, and the rest staminate. Flowers bloom in quick sequence from the outside toward center of umbellets so that fruiting begins while staminate flowers remain at anthesis.

The perfect flowers have no sepals, five white petals, five stamens, and a pistil of two united carpels with two free styles. As flowers open, stamens are curved inward before becoming erect. Stamens and knob-like anthers are initially white, but anthers become light tan as pollen develops. Styles have an enlarged base, the stylopodium, a characteristic of most species in the carrot family. The inferior ovary bears white hairs along longitudinal ribs, similar to the ciliate hairs of the floral bracts. The open corolla is ⅛ inch wide; the ovary at its tip, just below the corolla, is about 1/16 inch wide.

Staminate flowers, about 1/16 inch wide, have more slender pedicels and small bowl-shaped receptacles. Petals and stamens of staminate flowers are similar to those of the perfect flowers, however, the petals remain crimped together–the corolla does not flare outward.

Photo 5: This compound umbel has four umbellets of which the lower three have perfect and staminate flowers while the upper umbellet has staminate flowers only. Stigmas are held well above corollas. Note ciliate pubescence of bracts and bractlets and the ribbed ovaries.

Ovaries that are fertilized mature into long (to 1 inch) slender dry fruits called schizocarps that split into two 1-seeded halves called mericarps. These are slightly flattened and have longitudinal ribs with stiff forward-appressed hairs. Styles are persistent on the mericarps as spiny projections. At maturity, mericarps separate from each other and from the central axis so that only their tips cling to the tip of the central axis. At full maturity, black mericarps are slightly curved with a long spiny proximal tip and a short spiny distal tip (the persistent style). As various animals or birds brush against plants, the spiny tips and side-hairs become entangled in fur and feathers, providing seed dispersal.

Photo 6: In mid-June, schizocarps have split into two mericarps that cling to tips of the central axes. Upper leaf section shows adaxial surface while lower leaf section shows abaxial surface. Dried remnant is the third leaf section. (Parts separated for photo.)

For a native plant garden or natural area with moist soil and partial shade, this non-showy perennial may add extra texture and help in-fill an area. This perennial member of the carrot family does not seem to self-seed agressively. Roots, flowers and leaves are edible in salads or as a garnish.

Fifty-five species of the Carrot family occur in Arkansas, of which a number have bipinnate leaves and compound umbels. Characteristics of aniseroot that aid in its identification include: 1) a perennial species, 2) branched tap roots that have an anise scent, 3) broad leaves with bluntly toothed leaflets, 4) short dense pubescence along stems, 5) umbellets with perfect and staminate flowers, 6) petals of perfect flowers that have clawed tips, and 7) linear fruits. Aniseroot can be separated from the only other Arkansas species in the genus, hairy sweet cicely (Osmorhiza claytonii), by aniseroot’s 1) shorter, less conspicuous pubescence, 2) styles that extend outside corollas, 3) fruits that have prominent spiny hairs on longitudinal ribs, and 4) a stronger anise scent.

*  The word “anise” relates to a non-native culinary species (Pimpinella anisum) which has roots and leaves that also have an anise scent. “Long-style” compares aniseroot’s style to the shorter style of hairy sweet-cicely (Osmorhiza claytonii). The word “cicely” probably originates from European sweet-cicely (Myrrhis odorata). Aniseroot is also called “smooth sweet-cicely” based on its lesser degree of pubescence, as compared to hairy sweet-cicely.

Article and photographs by ANPS member Sid Vogelpohl

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Know Your Natives – Mayapple

Mayapple (Podophyllum peltatum) of the Barberry (Berberidaceae) family is an herbaceous perennial that has one or two large leaves per stalk. The genus name is from Greek words for “foot” and “leaf”, in reference to the appearance of  the leaves. The specific epithet, from Latin, is a reference to the vegetative leaf’s umbrella-like form, in which the petiole joins the leaf blade on its lower surface rather than the margin. In the U.S., mayapple, the only North American species of Podophyllum, occurs from Texas to Minnesota eastward to the Atlantic and Gulf Coasts. In Arkansas, mayapple occurs statewide. (A second species of Podophyllum occurs in east Asia.) Habitat consists of shady to partially sunny, mixed deciduous forest and forest edges with dry to mesic soils, along with moist open areas. Plants are also called American mandrake based on the superficial similarity to the unrelated European mandrake, Mandragora officianarum.

Mayapple develops an extensive shallow layer of reddish brown, rope-like rhizomes, to ¼ inch in diameter, that elongate annually by adding 2- to 8-inch-long straight segments. The ends of the segments have numerous down-turning fleshy white roots. Rhizomes do not have any noticeable growth nodes. With several new rhizomes branching from the ends of previous years’ segments, open to dense colonies may form with hundreds of leaves.

In late winter, vegetative growth develops from the terminal buds on previous years’ rhizome segments. The first growth to appear is a white “cone” formed by several imbricated protective bracts. As one to two large leaves develop, the cone spreads open. At first, leaf blades are down-drooped around hidden stalks so that the flat white centers of the leaves are the first leaf-portion to appear out of the cones. In the case of two-leaf stalks, two white centers appear, separated by an ovoid flower bud. Stalk growth quickly frees the growing furled leaf blades from their protective cone and they open umbrella-like.

Photo 1: This 3-inch tall, two-leaf stalk has furled leaves separated by a flower bud. Basal protective bracts quickly fade as stalks grow. Note marginal ciliate pubescence. Photo – March 16.
Photo 2: Terminal buds of previous year’s rhizome segments produce new stalks (extending off top of this photo). Basal protective bracts have become tissue-thin. White nubs will become new rhizome segments. Fleshy roots are concentrated below stalks. Photo – April 5.

Stalks, 1½ to 1¾ feet tall and ¼ inch in diameter, are erect, terete and glabrous. Stalks that support two leaves are forked at about two-thirds their height so that stem-length above the fork is 3 to 6 inches. Stalks bearing one or two leaves are of similar height and have the same light green to reddish coloration. Stalks are totally smooth. At the end of the growing season, stalks quickly disintegrate, leaving a round scar on the persistent rhizome.

Leaves, to 14 inches across, have an orbicular outline with up to nine shallowly to deeply incised lobes, depending on leaf size. Lobes are obovate in outline and separated by deep clefts. Leaves are a medium green above, often mottled, and a lighter green below. The upper leaf surface is glabrous, the lower surface and margins densely short-pubescent. Venation is strongly recessed above–creating a smoothly wrinkled surface–and strongly expressed below, with main veins dividing distally and terminating at the apiculate tips of the lobes. 

Photo 3: This colony may be a single plant (a clonal colony) or a number of intertwined plants. Photo – March 30.

Leaf shape of one-leaf stalks, with center of leaf blade attaching to stalk, is peltate. Leaves of two-leaf stalks have fewer lobes, the “missing” lobes directly above the fork in the stalk, so that leaf shape becomes off-set palmate (point of stalk attachment not fully centered) to palmate (point of attachment at leaf margin). One leaf of two-leaf stalks tends to be smaller than the other.

The mayapple inflorescence comprises a single flower positioned in the fork of two-leaf stalks. When stalks first emerge, flower buds are positioned slightly above and between the emerging leaf pair. With stalk and leaf growth, buds become hidden well below the large leaves. Buds, on slender sturdy pedicels to 1½ inches long, have three light greenish bowl-shaped sepals that drop off as the corolla swells. With anthesis, the large (to 3 inches wide) white flowers face downward. (Several rare forms of mayapple are known to occur.*)

Photo 4: Inflorescence consists of a single flower in the fork between the two leaves. Red buckeye (Aesculus pavia var. pavia) in background. Photo – April 4.

Flowers have five to nine petals, 12 to 15 stamens, and a single superior ovary. The white, waxy, obovate petals are 1½ inches long and wide. Stamens have ¼-inch-long pale yellow filaments and ¼-inch-long light yellow anthers that release pollen as they dehisce (split) along their lateral margins. The light green ovary is tipped by a prominent, pale yellow, crinkled stigma atop a short, stout style. Flowers are fragrant. Ovules are massed on a single broad placenta along one side of a central cavity.

Photo 5: Buds (bottom of photo) have three light-green sepals that drop off as flowers open. Flowers have five to nine overlapping petals, 12 to 15 stamens, and a large ovary (hidden in photo by crinkled stigma).
Photo 6: This half-inch-long ovary was dissected just after anthesis. Ovules are attached to a single placenta on the ovary wall.

A fertilized flower produces a berry that ripens in mid-summer. Mature fruit, about 1½ inches long, becomes pale yellow as leaves and stalk wilt and dry. Fruits drop to the ground where they become accessible to various small mammals as well as box turtles (Terrapene carolina), resulting in seed dispersal. The smooth seeds resemble apple seeds.

Photo 7: Leaves (at top of photo) have dried, while fruit remains green. Fruits have a flattened side. Prominent stigma is persistent. Photo – June 13.

Mayapple’s conspicuous foliage and colonizing tendencies may be welcome in a woodland garden or natural area where it would add a dramatic flair. The easily viewed parts of flowers and fruit can make it an educational tool. Gardeners can easily establish new colonies by transplanting rhizome segments as foliage declines. All above-ground evidence of plants disappears from summer until spring. Ripe fruit, with seed removed, is considered to be edible while all other portions of the plant (including unripe fruit) are known to be toxic. Mayapple contains podophyllotoxin, which is used in developing prescription drugs and for cancer research. Foliage is not eaten by deer or rabbits.

* Podophyllum peltatum forma deamii has pink-tinged flowers and maroon fruit. Podophyllum peltatum forma polycarpum produces a cluster of fruit. Podophyllum peltatum forma biltmoreanum produces orange fruit.

Article and photographs by ANPS member Sid Vogelpohl

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Know Your Natives – Southern Corydalis

Southern corydalis (Corydalis micrantha subsp. australis)* of the Poppy (Papaveraceae) family, formerly of the Fumitory (Fumariaceae) family, is an over-wintering annual that reproduces both sexually (chasmogamous flowers, which are cross-pollinated) and asexually (cleistogamous flowers, which are self-pollinated). In the U.S., it occurs from Texas and Louisiana, north to Kansas and Illinois, and then east along the Coastal Plain from Mississippi to North Carolina. In Arkansas, the subspecies is scattered throughout the Interior Highlands and West Gulf Coastal Plain. The genus name is the ancient Greek name of the crested lark, referring to the spur of the flowers. The specific epithet, also from Greek, means “small flower.”  The subspecific epithet is Latin for “southern.” Habitats vary from wooded floodplains, to open woodlands, to waste areas, roadsides and other disturbed areas, frequently in sandy soils.


Southern corydalis is a low-growing plant with a short taproot that terminates with many thin long fibrous roots. The plant germinates by winter and dies by early summer. The widely spreading, ascending to reclining, slender stems are square in cross-section with widely scattered alternate leaves that grow from the corners of the stem. When not confined by other plants, its multiple stems (to 11 inches long) radiate in all directions. Early growth tends to be bluish (glaucous) while a mature plant typically has light dull green leaves. Stems and petioles tend to be reddish. The glabrous (hairless) plants regenerate by seed only. Fruiting capsules of chasmogamous and cleistogamous flowers have the same appearance.

Plants in late winter have a cluster of basal leaves. With stem growth, compound cauline leaves and axillary leaves become distinguishable. Petioles (leaf stalks) of cauline leaves have a clasping base, a rounded lower surface with a central ridge (a continuation of the stem corner) and a flattened to channeled upper surface. Petioles of axillary leaves are non-clasping and square. Cauline leaves have up to seven leaflets, axillary leaves typically five, arranged sub-alternately along the leaf rachis. Leaflets, ½ to 1 inch long, are deeply incised so that each leaflet has a terminal lobe and a pair of lateral lobes. Incisions of the leaflets result in margins that are crenulated and divided into rounded to short finger-like segments, with obtuse often mucronate apexes. As shown by the photos below, the leaves are lovely and delicate. The largest may be 3½ inches long and 1 inch wide.

Photo 1: New leaves are glaucous while older leaves of this annual plant have reddened in response to cold temperatures. Photo – February 21.

Photo 2: This plant with cleistogamous flowers at the time of photo has actively growing stems with long compound leaves. A single first-fruit can be seen at far-left. Photo – March 11.

 

Photo 3: This full-length stem has four axillary stems. The three lower axillary stems to the right have cleistogamous inflorescences, while the terminal raceme is chasmogamous.

Flowering occurs from mid-March into late April. Primary and secondary stems bear both terminal and lateral racemes. To 3 inches long, chasmogamous racemes have up to a dozen flowers with each flower subtended by an acute obovate sessile bract. The persistent bracts, to ⅛ inch long at flowering and ¼ inch at fruiting, have entire margins.  Cleistogamous racemes are often fewer-flowered.

Chasmogamous flowers are bright yellow, four-petaled and up to ⅝ inch long and ½ inch high (side view) and ¼ inch wide (front or bee’s eye view). Upper and lower petals have rounded faces and a central sharply depressed area expressed abaxially as a sharp keel. In side view, the upper petal extends sharply backwards, paralleling the lower petal, before rising slightly to form an inflated, round-tipped nectar-spur. The nectar-spur extends about ¼ inch beyond the pedicel (flower stalk). The flower’s corolla is slightly longer from the pedicel forward than backward to the tip of the nectar-spur.

Flowers also have a matched pair of lateral petals that are pressed together at the flower’s center to form what appears to be a rounded up-flared single petal. The combined lateral petals envelop a short style (atop an elongate ovary) and stamens that tightly surround the ovary. The two-lobed stigma is barely exposed at the flower center. The lateral petals are about ¼ inch long.

Photo 4: Main photo shows a raceme with chasmogamous flowers and fruit, each subtended by a bract. Lower inset: front of a flower, upper petal to left. Upper inset: stamens, ovary and stigma exposed.

Cleistogamous flowers bear very different petals. Upper and lower petals are significantly smaller than those of chasmogamous flowers, do not flare outward, and lack a nectar-spur. Diminutive lateral petals envelope anthers and stigma so that self-pollination occurs.

Photo 5: Display of a chasmogamous raceme (lower) and a cleistogamous raceme (upper), both with fruit capsules. A cleistogamous flower, with upper and lower petals removed, is positioned above. Squares are ¼ inch.

As flowering extends upward in the raceme, the ovaries quickly develop into bean-like, erect capsules as the raceme elongates to 6 inches or more. The 3/4-inch long or slightly longer capsules, beaked by a persistent style, from chasmogamous and cleistogamous flowers, have the same appearance. Each capsule comprises two valves enclosing a single locule or cell. Each of two placentas on the inner walls of the capsule, extending from base to apex, bear a single row of alternating seeds. While still green, capsules dehisce along two sutures to release about 15 shiny, black, dimpled, flattened-ovoid seeds, each measuring less than 1/16-inch across. The seeds carry a small, fleshy, clear-gloppy structure at their base called an elaiosome. Elaiosomes are ant food: seeds are transported to the ants’ nest where elaiosomes are eaten and the seeds themselves discarded–a remarkable but not uncommon dispersal mechanism. 

Photo 6: Fruits dehisce to disperse shiny seeds that bear gloppy elaiosomes (ant food). In this photo, one of two placentas can be seen at open-center of capsule (within shadow). Squares are ¼ inch.

Three other species or subspecies of the genus are found in Arkansas. Mealy corydalis (Corydalis crystallina) has ovaries and fruit that are covered in a gray or white mealiness. Mealy corydalis is usually found in prairies, often concentrated on prairie mounds.  Pale or yellow corydalis (Corydalis flavula) has smaller, usually paler yellow flowers and fruit that hang downward on long pedicels. Pale corydalis is usually found in riparian forests or other moist forests and woodlands.  Small-flower corydalis (Corydalis micrantha subsp. micrantha) has shorter, fewer-flowered, chasmogamous inflorescences that are not held well above the leaves, as well as shorter and stouter fruits (under 6/10 inch long).  Small-flower corydalis is apparently very uncommon in the state and is reported to grow on bluffs and rocky hills, on glade margins, and in riparian forests.

* Some recognize this plant at the species level, as Corydalis halei.

Article and photographs by ANPS member Sid Vogelpohl

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Know Your Natives – Crested Iris

Crested iris or dwarf crested iris (Iris cristata) of the Iris (Iridaceae) family is a low-growing iris that produces light blue flowers in early spring. In the U.S., it occurs from Oklahoma, Arkansas and Missouri east to Atlantic Coastal states. In Arkansas, the species occurs across the Ozark Plateaus, Arkansas Valley and Ouachita Mountains. The genus name is for Iris, the Greek goddess who personifies the rainbow. The specific epithet, from the Latin meaning ‘crested,’ refers to the flower’s distinctive crests (see below). Preferred habitat is well-drained, mesic, sandy to rocky, fertile soils in partially sunny woodlands.

Roots of crested iris emerge from thick, horizontal, underground stems called rhizomes that grow just beneath or at the surface of the soil.  Crested iris rhizomes alternate between thin and swollen sections. The prominent segments of these underground stems are modified nodes, tightly covered by persistent brown, scarious (papery) bracts, which are themselves modified leaves. The base of each bract inscribes a growth ring around the rhizome. Bracts mostly hide the light yellow epidermis of the rhizome; the solid tough rhizome interior is also light yellow. All vegetative growth, both above and below ground, originates from the rhizomes. A rhizome may produce several to as many as eight aerial stem growth points (apically and laterally) along with several new rhizome growth points (apically, after culmination of vegetative growth) that form new underground branches. Rhizomes do not produce new growth after the second year, but they persist so that thick mats may develop.

Photo 1: Display of an especially healthy underground clump showing brown rhizomes with fibrous roots and green, aerial growth. Photo–late March.

Aerial growth occurs as either vegetative stems or flowering stems. Both stem types have a short (less than 1 inch), slender central stem that bears flat, dagger-shaped, alternate leaves. Smaller leaves, lowermost on a stem, are imbricate and tightly encircle the round stem, while distal leaf growth forms an elongate fan with the leaves flattened in a single plane. The closely spaced node pattern of the rhizomes continues on the stems. 

Photo 2: With aerial growth, leafy vegetative stems and reproductive flowering stems become distinguishable. In this photo, three flowering stems are shown in the foreground, two to left and one to right. Photo–late March.

All leaves above the duff layer are a yellowish to medium green and glabrous (those in duff being whitish). Leaves have a broad base transitioning to a broader mid-leaf that gently tapers to the tip. Leaves, with parallel venation and smooth margins, are mostly straight, but apically may curve toward or away from the central hidden stem. Leaves are about 6 inches long and ½ inch wide.

Leaf size on a vegetative stem gradually increases distally, with a few significantly smaller leaves at the base and six to eight larger leaves above. Leaves have a tight pocket, an adaxial slit (toward the stem) in the lower portion that partially extends into the blade. As new leaves grow, one above another, each is initially sheathed by the previous leaf. The uppermost pair of leaves on flowering stems (1 to 2 inches long) forms an enlarged, sharply keeled pocket that protects developing flowers and fruits.

Photo 3: Leaves overall have a flattened, dagger shape, with new leaves initially sheathed by older leaves. Uppermost leaves of flowering stems have leaf pockets that sheath the flower bud and fruit. Photo–early April.

The terminal inflorescence consists of one or two flowers, with those of a colony tending to bloom in unison. Flowers are large and showy, 2 inches in diameter, typically an overall pale blue to lavender, but occasionally white. They have three sepals (falls), three petals (standards), and three style-arms. Hidden underneath each style arm is a stamen. The three showy components, in a radial pattern, are arranged in layers, the sepals lowermost, petals next, and style-arms uppermost. The petals alternate with the sepals and style-arms–the style-arms, and the hidden stamens, lie directly above the sepals. Sepals are united at their base to form a slender tube, to three inches long, that extends to the ‘inferior’ ovary hidden deep within the pocket formed by the two uppermost leaves of the reproductive stem. Sepals are 1¼ to 1½ inches long and petals are somewhat shorter. Style-arms are about 1 inch long.

 

Photo 4: Two reproductive or flowering stems and a vegetative stem. Note the sheathing of leaves by lower leaves and the opposing pair of ‘pocket-leaves’ that subtend flowers and hide the ovary. The long flower ‘throat’ is the tube down which pollen tubes grow to reach the ovules in the ovary. The ovules become the seeds.

Widely spreading sepals are obovate (narrow at base and broad above mid-section) with a broad marginal band of the overall flower color that surrounds a narrow purple band. From mid-sepal downward, the ‘signal-patch’ (the area of contrasting color) has three ridge-like crests (the basis for common and scientific names) that extend toward the flower’s throat. The golden yellow central ridge is vertically rippled (when seen from above) while rippled parallel ridges on either side are yellow on their inward side and white outside. The area between the three ridges is yellow with purple markings. The ridged area of the sepal is strengthened (to support large bees) while the remainder of the sepal’s surface is flimsy.

The widely spreading petals and style-arms are of uniform color. Petals are narrowly obovate to oblanceolate with the rounded apical portion and undulating lateral margins. Style-arms are oblong with a slightly tapered base and a rounded, up-turned fringed apex that has a deep v-notch.

Photo 5: Flowers of this plant are almost white. Sepals with colorful signal-patches are overshadowed by the shorter style-arms. Petals are positioned between and above the sepals.

A single large stamen is located directly below each style-arm, with the elongate anther pressed against the roof of the style-arm. The pollen-receptive stigma is slightly exerted from the tip of the style-arm’s abaxial surface. The grooved, triangular ovary, ¼ inch long, is hidden at the base of the long floral tube.

Photo 6: Sepals to left and petals to right. Style-arms remain in position; note long white anther directly below arm. Stigma is contained by style-arm. Note ovary’s position at base of style tube, an adjoining flower bud hidden by leafy bracts, and nodes along stem.

With fertilization, ovaries develop into capsules that remain hidden within the leafy pockets. Half-inch long capsules have a pointed-oval outline in side view and a triangular cross-section. Capsules dehisce within the leafy pockets. Small, dark-brown, roughened, oval seeds are less than ⅛ inch long. Seeds have a sticky appendage (viscid aril) that wraps over their top so that seeds may attach to birds and animals.

Crested iris, being a short plant with intertwined rhizomes, is a choice plant for a woodland garden or natural area, if it remains uncluttered by other vegetation. Partially sunny areas with various well-drained mesic soils are ideal. This blue-flowering plant survives temporarily dry soils, is not eaten by deer, and does not readily self-seed. It can be a delightful, low-maintenance, six-inch-tall ground cover.

Crested iris is one of eight species of the genus Iris that occur in Arkansas. Of the other seven, only the rare dwarf iris (Iris verna var. smalliana) is low growing. Dwarf iris, a species of conservation concern, typically has dark blue flowers with a golden signal-patch without crests and with rhizomes of a uniform narrow width.

Other irises in the state:

  • Zigzag or short-stem-iris (Iris brevicaulis)
  • Blackberry-lily (Iris domestica, formerly Belamcanda chinensis) – not native
  • Copper or red iris (Iris fulva)
  • Garden iris (Iris germanica) – not native
  • Yellow iris or yellow flag (Iris pseudacorus) – not native and invasive
  • Southern blue flag (Iris virginica)

Article and photographs by ANPS member Sid Vogelpohl

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Know Your Natives – Hairy Skullcap

Hairy skullcap (Scutellaria elliptica) of the Mint (Lamiaceae) family is one of nine skullcap species known to occur in Arkansas. The genus name is from the Latin scutella, a dish, in reference to the distinctive shape of the lower portion of the fruiting calyx (see below). The specific epithet refers to the leaf shape. The common name “skullcap” refers again to the unique form of the calyx, in particular the upper portion. This herbaceous perennial occurs in well-drained, sandy to rocky soils in partially sunny deciduous woodlands, woodland edges, and stream banks and terraces.  In Arkansas, it is only known to occur in the Interior Highlands.

Hairy skullcap, with a large number of slender, light tan, ropy roots, has a mature height of about 1 to 2 feet. New stems in late winter tend to be purple, but that color fades to a medium green with time. The plant, without runners or rhizomes, has up to a half-dozen erect square stems, with secondary, axillary stems arising along their upper portions. Main and axillary stems have terminal inflorescences. Axillary stems, in matched opposite pairs, are typically leafless except for leaves subtending the inflorescence. Stems are covered with dense short fine pubescence (tomentose), so that young stems appear fuzzy. As is true for all skullcaps, plants do not have a minty scent. Stems, although not woody, may persist over winter. Opposite leaf pairs are widely separated and decussate (adjoining pairs rotate 90 degrees).

Photo 1: Roots bear current-year and previous-year stems along with a bud for the next year. Inset: a tomentose stem and a pair of leaves (upper surface to left, lower to right).

Leaves below the inflorescence are up to 3 inches long and 1¾ inches wide, triangular-ovate, with scalloped margins (crenate). Leaf bases may be nearly straight (truncate) to rounded or slightly wedge-shaped (cuneate), with narrow strips of blade extending part way down the  petioles. Leaves, attached along the flat faces of the square stems, are a dark green above and a yellowish green beneath. Petioles, about ½ inch long, are rounded below and flattened to channeled above. In comparison with pubescence of the stems, that of the leaf blades is sparse, although longer and denser hairs occur along the primary and secondary vein below. Leaf margins are ciliate with short hairs.

Higher up the main stem, leaves that subtend axillary stems or flowers become gradually reduced, more elliptical, and with margins less crenate to entire. Also, petioles shorten and decurrent blade material may extend to the stem.

Photo 2: Opposite leaves are widely spaced on erect stems. A dead stem from the previous year remains at center-right. Photo – early April.
Photo 3: Upper leaves of the main stems subtend axillary stems or individual flowers. Leaf size and spacing decreases above. Photo – mid-May.

In mid to late spring, spike-like terminal racemes up to 4 inches long bloom over several weeks. Lower in the inflorescence, individual flowers are subtended by a leaf whereas higher flowers are subtended by small bracts (see below). Flowers, becoming more closely spaced up the raceme, are positioned in opposite decussate pairs. Sturdy, ⅛-inch-long pedicels, with two tiny basal bracts, extend out from the rachis at 45 degrees. Stems and rachises within the inflorescence have tomentose pubescence, becoming glandular on pedicels and calyxes.

Photo 4: Adaxial (left) and abaxial (right) surfaces of a leaf pair along with two racemes. Up-rachis, leaves become more elongate and less scalloped.

Flowers of all skullcaps have an oddly shaped calyx that becomes distinctively dish-shaped as fruits develop and the dorsal “skullcap” enlarges to become the prominent upper portion (see Photo 6 with both flowering and fruiting calyxes). With anthesis, a fist-shaped, closed corolla pushes out of the calyx, so that the skullcap is pushed backwards. The corolla’s tubular base bends sharply upward as the “fist” expands and opens. After the corolla drops off, the calyx again closes.

Corollas of hairy skullcap, about ¾ inch long, are elaborately bilabiate (two-lipped), with light blue to violet shades that fade into white accents. Lighter colors (often white) occur along the center of the lower lip and across the winged lobes of the upper lip. The upper lip is three-lobed: an upper lobe constricts to form a projecting, nearly-closed hood and two lateral lobes that “wing” outward. The lower lip has a broad, rather convex, notched central lobe and two down-flared lateral lobes. Flowers have two frontal orifices: the small upper orifice of the hood and the lower larger orifice formed by the two lips.

Flowers have four slender stamens and a slender style that are mostly hidden within the corolla tube and upper lip. Stamens, with their filaments fused to the lower portion of the corolla tube, occur as two pairs. The slender white filaments, with long hairs, bear two-lobed pubescent anthers that are positioned just inside the small orifice of the hood. The filaments surround a white style which extends from the four-lobed ovary to the opening of the hood. The small tapered stigma is slightly exserted. (When large bees land on the lower lip to collect nectar, the anthers are positioned to deposit pollen on the back of the bee or the stigma to collect pollen from the back of the bee.)

Photo 5: Base of tubular flowers bends sharply upward to an out-facing corolla. Anthers are hidden within the closed hood and stigma is slightly exserted from the hood.
Photo 6: Small bracts subtend flowers in upper portion of raceme. Flowers bloom sequentially from base to apex. Photo – mid-June.

Following anthesis, corollas quickly drop off. With fertilization, one to four ovules–one in each lobe of the four-lobed ovary–form seeds as the calyx enlarges to about ¼ inch. The fruit is a round, dark, one-seeded nutlet with numerous tiny wart-like tubercles across its surface. The calyx dries to a light tan color and the “skullcap” drops off so that nutlets may be dislodged by wind and rain. The “dish” section of the calyx remains on the dry plant into winter.

Photo 7: Display (a square = ¼ inch) showing the lower calyx section (on left – the dish section), the upper calyx section (on right – the skullcap section), and the tuberculate nutlets. (As shown, in reference to dish section, skullcap section is upside-down and reversed.) Photo – early September.

Hairy skullcap is appropriate for a partially shady garden or natural area with moist soils. This small- to medium-sized erect perennial herb has attractive foliage and beautiful, intriguing blue flowers. It does not have runners or rhizomes so that “extra” plants from self-seeding may be easily removed. Plants may be eaten by deer.

Nine species of skullcaps (one with three varieties) occur in Arkansas. They all have blue to violet flowers, but leaf shape can generally be used to distinguish hairy skullcap from the other eight species. A species with similar leaves is heart-leaf skullcap (Scutellaria ovata), but its leaf margins are more serrate and its adaxial leaf surface has a coarser appearance.

Species and varieties of skullcaps that occur in Arkansas:

  • Bush’s Skullcap (Scutellaria bushii)
  • Gulf Skullcap (Scutellaria cardiophylla)
  • Hairy Skullcap (Scutellaria elliptica)
  • Hoary Skullcap (Scutellaria incana)
  • Rough Skullcap (Scutellaria integrifolia)
  • Mad-Dog Skullcap (Scutellaria lateriflora)
  • Heart-Leaf Skullcap (Scutellaria ovata)
  • Southern Skullcap (Scutellaria parvula var. australis)
  • Glade Skullcap (Scutellaria parvula var. missouriensis)
  • Small Skullcap (Scutellaria parvula var. parvula)
  • South American Skullcap (Scutellaria racemosa) (non-native)

Article and photographs by ANPS member Sid Vogelpohl

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Know Your Natives – Ernest’s Spidewort

Ernest’s spiderwort (Tradescantia ernestiana) of the Commelinaceae (Spiderwort) family is an early-blooming, low-growing species, one of the 12 spiderworts that occur in Arkansas. The genus name honors John Tradescant, gardener to Charles I of England, while the specific epithet honors American botanist Ernest Jesse Palmer. This spiderwort occurs in Missouri, Oklahoma, Arkansas, Mississippi and Alabama. In Arkansas, the primary areas of occurrence are the northwestern portion of the Ozark Plateau, the Ouachita Mountains, and higher elevations of the Arkansas Valley. It is also known as woodland spiderwort. The name “spiderwort” has been ascribed to various origins.*

Ernest’s spiderwort occurs in moist sandy to rocky soils in shady to partially shady sites found along wooded slopes, bluffs, woodland edges and lowlands, as well as along drainages and open wet fields. This herbaceous perennial has a multitude of light tan, slender, fleshy roots that radiate outward at shallow depth. Leaves, emerging in mid-winter, are produced in separate basally sheaved, tightly-held clusters, each originating from a separate growth point on a broad, irregular caudex. New clusters develop alongside older clusters and from new growth points around or under the caudex. In favorable sites, dense expanding clumps may form. On any particular plant, a few or many clusters produce a central floral stem.

Photo 1: Some clusters of leaves may produce a floral stem. Inset, showing parts of same plant as in main photo, has arrows indicating developing new clusters. (Leaves damaged by cold temperatures.)

A cluster may have basal leaves only (non-blooming plants) or basal leaves transitioning to cauline (stem) leaves. Leaves higher on stem are spirally arranged and well spaced. Cauline leaves have basal sheaths, tightly wrapped around the stem, with the length of sheath decreasing toward a terminal inflorescence. Largest leaves, at mid-stem, may be to 11 inches long and 1½ inches wide. Leaves are arching and strap-like (broadly linear to lanceolate) and attenuate (gently tapering) to an acute apex. The long, arching and overlapping leaves, in-folded along the upper midrib, give the overall leaf mass an angular appearance. Leaf margins are straight to undulating and entire (uncut). While early leaves are highlighted with reddish shades, later leaves are a lustrous to dull medium green. Leaves are not glaucous (no white coating) and may be glabrous (no pubescence) to puberulent (short soft hairs). Venation is parallel and extends onto sheaths.

Photo 2: First leaves, appearing in mid-winter, may be reddish. Photo – mid March.

Mature plants produce main stems that may have a few secondary stems from the axils of upper cauline leaves. Stems are ascending to arching, glabrous to sparsely pubescent. All parts of the plant are somewhat succulent. With drying soils and warming conditions, plants go dormant by mid-summer; however, with improved conditions, plants may produce new growth. All above-ground evidence of plants disappears soon after they go dormant.

The inflorescences, with blooms from mid to late March into April, are in the form of umbels at the apexes of terminal and secondary stems. Umbels consist of flowers on slender pedicels about an inch or more long, situated between subtending pairs of sessile, leaf-like bracts at the tops of the stems. Pedicels may be glabrous or have short pilose pubescence (thin weak hairs). Length of stems is such that flowers remain within the leaf mass.

When buds first appear, they are pressed together in several stacks. Flowers reach anthesis sequentially, from uppermost to lowermost, initiating bloom when the stem first emerges. With only a few flowers of an umbel in bloom at one time, blooming may continue for a week or two. Buds and flowers are ascending, but after anthesis the spent flowers become nodding to drooping. Flowers open in early morning for a half-day (longer on cooler days).

Photo 3: A clasping, alternate cauline leaf can be seen on left stem along with opposite sessile bracts that subtend the inflorescence. Note tightly stacked buds on right stem. Photo – early April.

Flowers of separate plants range from light to dark pink, blue and purple (rarely white), with the color being shared by petals, filaments, wispy filament hairs, and style. Flowers, to 1½ inches in diameter, have three triangular, light green, boat-shaped sepals. When in bud, sepals are positioned margin-to-margin, forming a tear-drop-shaped calyx. At anthesis, the flower’s three sepals (½ inch long, ¼ inch wide) and three petals spread wide with tips of sepals positioned between petals. Petals are broadly ovate to almost orbicular and very showy. Upper petal margins are variously flexed and may be slightly irregular. Flowers have six ascending stamens with bright yellow anthers and exquisitely beautiful, wispy filament hairs, each hair consisting of single cells visibly connected end-to-end. The colored style, broader than the filaments, bears a white, terminal stigma. The plump ovary is three-chambered. With the passing of anthesis, the calyx again becomes tear-drop shaped and persists into fruiting. The exterior of the sepals is covered with dense, long, pilose pubescence.

Photo 4: Flowers may be light to dark pink, blue or purple. Note the six stamens (with wispy hairs and lobed anthers), single style atop a triangular ovary, and tips of sepals between the petals.
Photo 5: Calyxes, on growing pedicels, are positioned upright in bud and flower, but droop after anthesis. Plant to right is rose vervain (Glandularia canadensis).

With fertilization, three-chambered capsules form that have central placentation. The oval capsules dehisce (split) at their top and sides, spreading wide with the three sections positioned between the sepals. A capsule may produce a half dozen or so flattened, round gray seeds.

For a partially shaded to shady natural area that has moist to wet soils, Ernest’s spiderwort may be a desirable plant. Its mid-winter attractive growth provides early evidence of spring and its early flowers are a highlight of the season. Flower color of various plants varies from light to dark pinks, blues and purples. In more favorable sites, even a large plant remains a non-aggressive self-seeder. Plants disappear in summer, but may have re-growth when conditions improve.

Photo 6: Ernest’s spiderwort can form clumps. In comparison to some other taller spiderwort species, flowers mostly remain within the leaf mass.

Spiderwort species (Tradescantia spp.) are notoriously difficult to tell apart. In Arkansas, five common and seven uncommon spiderworts have been recorded. Characteristics of Ernest’s spiderwort that may help distinguish it from other spiderworts include 1) preference for shady sites, 2) early inflorescence, 3) darker flower colors, 4) wider leaves, 5) shorter clumping habit, and 6) pilose pubescence mostly on sepals and pedicels.

In Arkansas, similar species in similar habitats, easily confused with Ernest’s spiderwort, are the uncommon Ozark spiderwort (Tradescantia ozarkana) and the uncommon Virginia spiderwort (Tradescantia virginiana). Flowers of Ozark spiderwort are lighter colored (usually white) and have smaller sepals. In Arkansas, its range overlaps with Ernest’s spiderwort, and the two are known to hybridize. Virginia spiderwort typically has blue flowers and narrower leaves. It is at present only found in eastern Arkansas, outside of the range of Ernest’s spiderwort.

*   The term “spiderwort” has several possible origins: 1) leaf arrangement that looks like a “squatting” spider, 2) webby hairs on filaments, and 3) sap of stem can be drawn out into a webby string.

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Know Your Natives – Carolina Larkspur

Carolina larkspur (Delphinium carolinianum subsp. carolinianum) of the Buttercup (Ranunculaceae) family has irregular (bilaterally symmetrical) springtime flowers that are typically deep blue. The genus name is based on a Greek word for “dolphin”, in reference to the shape of flower buds (when viewed from the side). The specific epithet is a reference to one of the Carolinas, presumably the site of the type collection, i.e., the collected specimen upon which the species is based. In the U.S., the species Carolina larkspur occurs from New Mexico to North Dakota, east to Wisconsin, Kentucky, and South Carolina, and south to the Gulf Coast. The typic subspecies discussed here occurs from northeastern Texas and Louisiana, north to Iowa and Illinois, and across the Southeastern states. In Arkansas, it occurs throughout much of the state except for low lying areas of the Mississippi Alluvial Plain and West Gulf Coastal Plain. Habitat preference is sunny to partially sunny, dry-mesic to dry sandy or rocky woodlands, glades, prairies and roadsides on various substrates. The species is also known as blue larkspur and wild larkspur.

Carolina larkspur is an herbaceous perennial. It has a ground-hugging rosette of basal leaves in mid-winter, flowers in early spring, and mature fruit in late spring, after which the plant becomes dormant. 

The plant has basal and stem (cauline) leaves that, in outline, have an overall round to triangular shape. Leaf blades are deeply, palmately cut into three primary lobes, a terminal lobe and two laterals, and may be 3+ inches long and wide. Leaves are medium green adaxially, with lighter colored primary veins, and a lighter yellowish green abaxially. Blade and petiole are finely short pubescent to glabrate. Petioles, slender with a widened base, are round in cross-section with a flattened adaxial side . Venation is recessed above and expressed below, with the lower midvein being channeled.

Lobes of the earliest basal leaves have a wedge-shaped base and a fan-like apex. As additional basal leaves grow, their lateral lobes become deeply incised (though not reaching the petiole) so that leaves appear to have five primary lobes. With subsequent new leaves, lobes become more subdivided and sinuses more incised, till ultimately the blades comprise narrow, finger-like lobes, resulting in a “skeletal” appearance. Regardless of the degree of subdivision, lobing retains a pattern-of-three. Basal leaves wither, in age sequence, as the inflorescence develops.

Photo 1: Trifoliate character of leaves is readily seen in older basal leaves. Degree of leaf incision increases with later leaves. Photo – late January.
Photo 2: Structure of basal leaves become increasingly complex; however, trifoliate character of leaf blade and lobes is maintained. Photo – early March.

Stem leaves are widely spaced from stem base to immediately below the inflorescence, where they are replaced with bracts (see below). Leaves are arranged alternately, with lower stem leaves similar to the upper basal leaves. Leaves at the stem base have slender petioles to 6+ inches long; petioles are shorter about mid-stem and absent (leaves sessile) just below the inflorescence. Up-stem, both the size of the leaf blades and the complexity of their lobing decrease. Leaf coloration and venation are the same as that of basal leaves.

Photo 3: As the floral stem develops, the earliest wider-lobed basal leaves have withered. Remaining leaves have a “skeletal” appearance. Lowermost stem-leaves have especially long petioles with widened bases. Photo – late March.

Main stems, to about four feet tall, are erect, straight, terete and, typically, have downy pubescence (puberulent). (A shorter larkspur species that has similar basal leaves and blue flowers is dwarf larkspur, Delphinium tricorne.) Main stems support a raceme that may be a foot or more long. More robust plants may have shorter secondary stems growing from leaf axils at about 45 degrees that support shorter secondary racemes. Flowering proceeds from base to apex with fruits (capsules) already maturing at base as upper flowers continue to bloom. Flowers are each directly subtended by a pair of small opposite, linear bracts.

Photo 4: This robust plant is developing secondary stems at leaf axils along upper portion of main stem. Leaf size and degree of lobing decrease up-stem. Blooms of a much shorter dwarf larkspur can be seen in background. Photo – mid April.
Photo 5: A natural stand of Carolina larkspur in a sunny, rocky glade. Stem at left-foreground bears seed capsules, as upper flowers continue to bloom. Photo – Mid May.

Larkspurs are among the showiest of our native wildflowers. Close examination reveals that it is the petaloid sepals, rather than the petals themselves, that create the main attraction. Flowers, measuring about 1½ inches long and an inch wide, are typically a deep blue, but may be purplish or white. The symmetry is bilateral, described technically as irregular or zygomorphic, with one sepal of the dominant calyx positioned above the flower center and two sepals to either side. From the front of the flower (bee’s eye view), all sepals look the same, broad with a rounded apex and a distinct indentation on the face that corresponds with a green protrusion on the back. However, when viewed from the side, a half-inch-long, up-curved elongate, conical spur extends from the back of the upper sepal. 

Flowers also have four irregular petals that are significantly smaller than the sepals and are generally the same color, but petals may have various markings and color shadings. A matched pair of upper petals is very dissimilar to a matched pair of lower petals. While the sepals are thin in texture, the petals are thickened. The upper petals have an exserted up-flaring triangular portion with larger semi-tubular spurs that extend backward and are enclosed within the spur of the upper sepal.  This complex, compound tube serves as the nectary.

Lower petals, trending downward, are distally broad, rounded, and v-notched. Their outer surface bears long white twisty hairs, especially centered along the notches.

Stamens, pistils and ovaries are hidden below the lower pair of petals, although anthers may be partially visible. Three elongate, stubby whitish ovaries, fused to one another, directly above the pedicel, are in close contact with a number of stamens. Ovaries have stubby tapered styles tipped with the stigmas. Stamens have white flattened twisty filaments and dark elongate anthers.

Photo 6: Five sepals dominate the flowers’ appearance. Four irregular petals are grouped at center. Reproductive parts of flowers are mostly hidden by the two lower petals. Photo – late April.
Photo 7: A larkspur flower exploded to show parts (not Carolina larkspur). #1 – pedicel with pair of bracts. #2 – lower pairs of sepals. #3 – Upper sepal with partial spur; arrows indicate points of attachment. #4 – Upper pair of petals;  arrows indicate point of attachment (note semi-tubular shape with closed distal end). #5 – lower pair of petals. #6 – stamens. #7 – pistils (two of three shown).

The fruit of a fertilized flower comprises three slender, erect, dull-green follicles that are ½ to 1  inch long and fused together below to form a kind of three-parted capsule. The base of the capsule has a raised ring (calyx scar). Follicles are beaked with remnants of their  styles. When dry, the tannish papery follicles split, each along an inward suture at the upper end. Seeds drop free through the opened sutures or when follicles disintegrate. Tannish seeds have roughened, rounded and flattened surfaces.

Carolina larkspurs do well in rocky, sunny sites where soils are well drained. In a garden setting or natural area, mid-winter basal growth provides early greenery. Later stems provide early height to a garden, and blue flowers add dramatic impact, either singly or in groups. Larkspurs are attractive to various bees, including bumblebees, which often take the nectar by piercing the spur. An infestation of aphids can wipe out the inflorescence. Delphiniums are known to be toxic to humans and mammals. 

Two other subspecies of Carolina larkspur grow in Arkansas, both uncommon in the state: pinewoods larkspur (D. carolinianum subsp. vimineum) and plains larkspur (D. carolinianum subsp. virescens). Both are known in Arkansas only from the southwestern portion of the state. In comparison to Carolina larkspur, pinewoods larkspur has fewer, larger leaves with longer petioles and each with three primary, wider divisions. It occurs in sandy soils and is restricted to the Coastal Plain, ranging primarily in south-central and eastern Texas and western Louisiana. Plains larkspur also has fewer leaves with longer petioles, and white to light blue flowers.  It grows throughout the Great Plains, especially in prairies.  Both retain their basal leaves while the plants are in bloom, in comparison to the typic subspecies.

In addition to dwarf larkspur (D. tricorne, noted above), two other species are found in the state, namely, Moore’s delphinium (D. newtonianum) and Trelease’s larkspur (D. treleasei), both of very limited distribution in north (and west-central = Moore’s) Arkansas. Moore’s delphinium grows in moister, shaded sites and has less divided stem leaves and more diffuse inflorescences that bloom from apexes to the bases.  Trelease’s larkspur has flowers on long pedicels and grows exclusively in dolomite (a calcareous type) glades in the central Ozarks Highlands.

Article and photographs by ANPS member Sid Vogelpohl

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