Know Your Natives – Eastern Prickly Pear

Posted on January 28, 2018 by ANPS Webmaster

Eastern prickly pear (Opuntia humifusa, formerly Opuntia compressa)* of the Cactus (Cactaceae) family is a mostly prostrate stem-succulent with large, bright yellow, spectacular flowers. Like most members of its family, the species is adapted to thrive in arid habitats. Interestingly, the cactus family (with the exception of a single species) is native only to the New World. Cactus-looking plants in African and Asian deserts typically belong to either the Spurge (Euphorbiaceae) or the Milkweed (Asclepiadaceae/ Apocynaceae) families.

The genus name, Opuntia, originated in the first century for a cactus-like plant found near Opus, Greece. The specific epithet “humifusa,” from Latin for “spread out,” refers to the plant’s growth habit. Eastern prickly pear, the most widely spread cactus in the eastern U.S., occurs from New Mexico and Colorado east to Connecticut and south across all interior states to the Atlantic and Gulf Coasts. In Arkansas, it occurs across the state except for the Mississippi Alluvial Plain and lower elevations of the West Gulf Coastal Plain. Other common names include devil’s-tongue and common prickly pear.

Eastern prickly pear occurs as scattered individual plants or may form a mat-like colony over time. A succulent species, it is highly tolerant of drought and, unlike most cacti, cold temperatures. It grows well in a wide variety of habitats, varying from full-sun rocky hillside glades and sandy prairies to woodland openings with partial sun. Plants do well in xeric to dry-mesic soils that may range from acidic to alkaline. Plants in areas of encroaching tree cover often die out due to lack of sunlight.

Prickly Pear - Opuntia humifusaPhoto 1: This two-year plant has a round stem at its base and a broadened stem above. With maturity, fewer spines will be present.

Eastern prickly pear is composed mostly of water-storing stems with the lowermost portion being round in cross-section while the remainder of stem comprises thick, flattened, oval to obovate segments (pads or cladodes) that grow chain-like from the upper margin of one pad to the next. Stems to 3 feet long are prostrate, except for terminal pads that may stand up to 8 inches or so. The lowermost portion of the stem extends into soil as a stub from which a few long fibrous roots extend out at shallow depth for several feet. Size of pads is dependent on habitat, but pads may be 5 inches long, 3 inches wide and ½ inch thick. New pads, growing from the distal margins of previous year’s pads, break-off easily and, when in ground contact, can root to form a new clonal plant. The lowest portions of mature plants become woody.

During the growing season, mature pads have a medium green to blue-green waxy, glabrous surface marked by regularly arranged areoles positioned diagonally across both sides of pads and also along upper pad margins. All areoles have tight tufts of short hair-like reddish bristles (glochids) with barbed tips. Areoles on upper sides of pads and along upper pad margin may bear one or two light-colored, stout, needle-like spines to 3 inches long (spines sometimes absent on pads or entire plants). Areoles along upper margins of pads also produce new pads or flowers (see below). Both glochids and spines are painful to human touch; however, the short glochids can be more painful due to their flesh-retaining tips. They are also much more difficult to remove. During drought and with approaching winter, pads lose water content and become thin and wrinkled, but quickly revive with improved conditions.

Prickly Pear - Opuntia humifusaPhoto 2: This plant, which may be four years old, does not have any spines. Note the diagonally arranged areoles with tufts of glochids. Photo in late August.

When new pads develop, side and marginal areoles bear single, short, narrowly conical (subulate) ¼ inch, more or less, vestigial leaves. These leaves quickly drop off, leaving all food-making function (photosynthesis) to the green stems.

In late May into June, solitary flowers grow from areoles along the distal curved margins of previous year’s pads. Multiple flowers may grow from a pad. Early on, flower buds have light green triangular sepals that cover several overlapping series of tepals (sepals transitioning into petals). Flower buds are prominent with a short-conical shape (when seen from side) and are positioned at the tip of inverted-cone-shaped elongate ovaries that are several times longer than buds. Ovaries are glabrous with diagonally arranged, well-spaced, spineless areoles along with a ring of areoles outlining the wide, distal end. The ovarian areoles have the same leaves as new pads, but without spines. Ovaries are slightly ridged.

Prickly Pear - Opuntia humifusaPhoto 3: In this mid-May photo, a previous year’s pad bears a new pad and two flowers growing from areoles at its upper margin. Areoles of new pad bear short conical leaves that will quickly drop off.

At anthesis, the perfect (with male and female parts) diurnal flowers, to 3 inches across, show light to bright yellow overlapping waxy petals. The eight or so petals in the upper series have narrow bases and a broad upper portion with a central point and often two side points. Uppermost petals may or may not be marked by a reddish-orange “flame” that extends upward from the base. Underlying series of petals gradually change shape, grading into the lowermost series. Flowers have numerous short stamens, with light yellow elongate anthers on darker yellow filaments, that encircle a single, white, stout style tipped by a bulbous partitioned stigma.

Prickly Pear - Opuntia humifusaPhoto 4: This orange-centered flower has three points on its petals. Triangular green sepals can be seen on the bloomed-out flower to the right. A young pad behind this flower still bears its small conical leaves.

Spent flowers quickly fall from the ovary (developing fruit), exposing a concave scarred upper surface. As the elongate fruit (berry) matures, it becomes fleshy and purplish. Fruits remain on the stem into the next growing season. Fruits contain 20 to 30 light colored, flattened and circular seeds that have an indentation on one margin and a protruding edge all around. Seeds are dispersed by small mammals and birds.

Prickly Pear - Opuntia humifusaPhoto 5: Central pad bears five flowers and no new pads. Light colored lines across old pads may result from pad shrinkage during winter or droughts. Photo in early June.

Prickly Pear - Opuntia humifusaPhoto 6: In this early January photo, the two fruits are 2½ inches long and ½ inch in diameter. Inset shows seeds in a fruit as well as three cleaned seeds that bear imprint of embryonic plants.

In a garden setting, eastern prickly pear may be suitable for xeriscape and rock gardens where the plants could remain untouched and where other vegetation would not invade the area. Plants can be easily started by setting the end of a detached pad at the chosen permanent site. Eastern prickly pear is a dependable bloomer. Fruit and pads of prickly pears are edible and may be found in grocery stores labeled “nopalito” (pads) and “tuna” (fruit). However, care must be taken to remove the glochids from pads of our native species.

Along with eastern prickly pear (Opuntia humifusa), a second native cactus occurs in Arkansas, namely, western prickly pear (Opuntia macrorhiza)*. This second species is recorded from scattered counties in the Interior Highlands. Opuntia macrorhiza, also known as plains prickly pear, has more than two spines per areole, with spines occurring in areoles across the entire pad surface. It is also sometimes reported to have thicker, tuberous roots in comparison.

*The taxonomy of the genus Opuntia is widely debated. The treatment presented here follows the traditional (and most simplistic) view of Arkansas prickly pears. However, some authorities believe we have several additional species within the state, but delineation of those species and the most appropriate application of names to those species is not settled. Some of those authorities believe we do not have true Opuntia humifusa in Arkansas, this being a species more confined to the Northeast. The name Opuntia cespitosa may sometimes be found applied to the common prickly pear in Arkansas traditionally called Opuntia humifusa. To make things even more confusing, hybrids have been reported within the genus.

Article and photographs by ANPS member Sid Vogelpohl

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Know Your Natives – Resurrection Fern

Posted on January 16, 2018 by ANPS Webmaster

Resurrection fern (Pleopeltis polypodioides var. michauxiana), formerly Polypodium polypodioides, of the Polypody (Polypodiaceae) family is an evergreen fern that occasionally appears to die in periods of dryness while being “resurrected” when again moistened. The genus name is from Greek words meaning “many” and “shields” (see “peltate scale” below). The specific epithet is based on Greek words for “many” and “foot”, in reference to its rhizomes. In the U.S., resurrection fern is found from Texas to southeast Kansas to Delaware, thence southward to the Atlantic and Gulf Coasts. In Arkansas, it is known from every county. (The species, with its several varieties, has an extraordinarily wide range, occurring in South America south to Argentina as well as in Africa.) Other common names (based on its former classification) include little gray polypody and scaly polypody. Resurrection fern grows on living or dead tree trunks and branches, as well as on rocks. (Although resurrection fern is usually found growing on living trees, it is an epiphyte, not a parasite nor, like mistletoe, a hemiparasite. Plants get neither food nor water from their hosts, only a perch.) They derive much of their moisture and nutrients through their leaves from the air and surrounding dampness. They are often found in association with mosses. Sun exposure and available moisture are variable.

Resurrection fern is a low-growing, creeping plant with long, 1/16-inch-diameter, well-hidden rhizomes that follow surface irregularities of tree bark and other surfaces. Rhizomes, strongly attached to the host by roots, are covered with dense, thin, acicular  and light-colored scales. Rhizomes are profusely branched so that mats form in favorable sites, such as on tree trunks and across tree limbs.

Photo 1 Jul 2Photo 1: With dry conditions, fronds shrivel and curl with blade undersides turned upward. Photo in early July.

Photo 2 Jan 8Photo 2: In this early January photo, resurrection fern (growing among moss) was damaged when tree limb was cut for firewood, thus exposing rhizomes. Note linear scales pointing in direction of rhizome growth.

Leathery leaves (fronds), ascending or descending from the upper sides of the rhizomes, measure up to about 9 inches long and 2 inches wide. They are broadly lance-shaped and deeply once-divided (pinnatifid), with up to 15 or more pairs of alternate, blunt-tipped lobes (and a single terminal lobe at the apex). Fronds are glabrous and dark-green above and a light grayish-green beneath. Lobes, 1/8 inch wide, are oblong to elliptic with wide bases, entire or with slightly wavy margins, and are generally slightly wider at the middle, tapering gently toward the tip. Petioles (stipes), about a third the length of the frond, are round in cross section with a flattened top. Other than the midrib, which is depressed above and expressed below, the only other obvious venation is the midveins of the lobes, the lesser veins being obscure.

Although fronds may be green at any time of the year, during dry conditions, they shrivel (losing most of their water content*) and become grayish, turning their lower surface upward to better absorb incoming moisture. Upon return of moist conditions, scales on the lower surface absorb moisture and pass it on to the living tissues of the leaf–the “resurrection” of a withered, apparently dead organism into a lush green plant.

Photo 3 Dec 6Photo 3: An isolated fern colony anchored to a vertical rock outcrop.

The lower surfaces of the lobes are covered with small (1/16 inch), flat, overlapping scales, attached at their reddish brown centers (peltate) and surrounded by broad, transparent to light gray, more or less entire margins. Scales are numerous, variously sized, and concentrated along the blade’s midrib, from where they continue down the lower, rounded side of the stipe (petiole). The lower, rounded surface of the stipes also has dense, transparent, lanceolate scales and reddish brown hairs. The upper flat surface of stipes is glabrous.

Photo 4 Dec 6Photo 4: New fronds unfurl on which developing peltate and lanceolate scales can be seen.

Resurrection fern (and all other true ferns and their allies) produce new plants through spores**. Both fertile and sterile fronds have the same shape (monomorphic). In summer into fall, fertile fronds produce up to 80+ ball-shaped sporangia (structures in which spores develop) aggregated into discrete, flattened and rounded to oval “fruit dots” (sori). Fruit dots, on lower sides of lobes, tend to be on the upper ¾ of fertile fronds and on the upper half of their lobes. Fruit dots, near lobe margins, occur in rows on either side of the central veins. They develop without the protective cover (indusium) that is typical of many genera of ferns. Initially, sporangia are yellow but become brown as they mature and split open. With the splitting of the sporangia, dust-like spores are released to the breezes. The presence of sori on the underside of fronds results in a prominent raised area (pock) directly above it on the upper surface.

Photo 5 - Oct 14Photo 5: Upper side (left) and lower side (right) of fertile fronds. Pocks on left frond correspond to sori on the underside, as seen on frond at right. Frond on right shows, as well as sori, numerous peltate scales, which are found on fertile and infertile fronds. Photo in mid-October.

Resurrection fern can be “transplanted” by attaching a fern-bearing fallen tree limb to another tree or rock in a mostly shady, generally moist site. The fern-covered tree limb (or a fern division) must be firmly attached to its new host so that new rhizome growth will attach.

A second member of the Polypody family is also found in Arkansas, namely, rock polypody (Polypodium virginianum), and it may be mistaken for resurrection fern. Both species have similar leaf shape, but resurrection fern has narrower rhizomes and shorter fronds.  Fronds of rock polypody can be over a foot long.  The definitive characteristic to separate these two species is the peltate scales found on resurrection fern, but not on rock polypody. Also, rock polypody prefers consistently moist sites on rocky bluffs and boulders, rather than trees.  In Arkansas, it occurs primarily in the Ozark Mountains with a few occurrences as far south as Logan and Polk Counties.

  • Resurrection ferns can lose 95% of their water content and survive. Their cells have proteins (dehydrins) that, with increased numbers when the plant dries, concentrate along cell walls preventing cells from totally collapsing.

**  Spore-producing plants are called ” sporophytes”.  They represent the diploid phase of a complex life cycle that–you may remember from your last botany or biology course–goes by the name of “alternation of generations”. A spore germinates in soil to become a prothallus (the haploid or “gametophyte” phase of the life cycle), a thumbnail-sized, non-vascular, alga-like plant.  The tiny prothallus produces gametes: both mobile sperm and attached eggs.  With fertilization of the egg, a diploid zygote can develop into a new diploid sporophyte plant–and start the cycle over again.

Article and photographs by ANPS member Sid Vogelpohl

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Know Your Natives – Jerusalem Artichoke

Posted on December 29, 2017 by ANPS Webmaster

Jerusalem artichoke* (Helianthus tuberosus) of the Aster (Asteraceae) family is a large, tuber-producing perennial that was an important food source for Native Americans and early settlers. The genus name combines two Greek words for “sun” and “flower”. The specific epithet is from Latin and means “with tubers”. This species occurs throughout the eastern U.S., as well as in eastern Canada, with scattered, presumably introduced occurrences in the western U.S. In Arkansas, it occurs across the northern half of the state and in scattered southern counties. Its preferred habitat is partially to fully sunny sites with moist loamy soils, such as found in creek and river floodplains and roadside ditches. Other common names include Canada potato, sunchoke (a commercial name), and girasole (Italian for “sunflower”).

In late summer into fall, in addition to the plant’s fibrous roots, thicker roots radiate out from the underground portion of the stem. These thicker roots terminate with light tan to reddish, stubby to elongate tubers that may be mostly smooth or knobby. Tubers may be 4 inches long and 2 inches across. These thin-skinned tubers are white and potato-like inside. Tubers, encircled by well-spaced growth rings, have a main bud at their distal end along with scattered secondary buds, especially on knobby projections. With maturity of tubers in mid-fall, parent stalks and roots die. Plants can produce numerous tubers so that thick colonies can grow over several years.

Jerusalem artichoke - Helianthus tuberosusPhoto 1: Along with a main bud (whitish tips), tubers also have smaller secondary buds. Growth rings encircle tubers. Upper large tuber is 2¾ inches long, ¾ inch wide. Photo in early December.

Spring growth, directly from over-wintering tubers, begins with appearance of leaves attached to a main stem. Through the growing season, stout erect stems may reach 4 to 10 or more feet. Round stems with short, stiff, white pubescence (scabrous) are generally a medium green but may be purplish. Main stems, to ¾ inch in diameter, feel bristly. Long branches grow from upper leaf axils, while short branches may grow from lower leaf axils.

Jerusalem artichoke - Helianthus tuberosusPhoto 2: Parent plant having died, new plants grow from tubers in mid-March.

Jerusalem artichoke - Helianthus tuberosusPhoto 3: Plants in this colony are showing early upper branches. Plants in foreground have been browsed by deer.

Leaves are medium green on upper surface and lighter green on lower surface, with an underside that is smooth due to soft pubescence and a scabrous upper side due to stiff, short pubescence. Leaves, widest at their bases, gradually taper to a point (acuminate). Largest leaves, typically occurring in opposite pairs below the inflorescence, are elongate-triangular with a blade up to 10 inches long and five inches wide on a 4-inch petiole. These largest leaves–pairs may be 5 or more inches apart along the stem–have a truncated base and serrated margins. Petioles of larger leaves are partially winged. Petioles of opposite leaf pairs are narrowly connected around the stem. Smaller alternate leaves, higher in the inflorescence and on short branches, are lanceolate with entire margins and have petioles that tend to be winged their entire length. Smaller alternate leaves also occur on short branches that occur below the inflorescence.

Primary venation consists of three prominent veins, namely a central vein or midrib and a pair of lateral veins that branch off midrib near its base. The two lateral veins gently curve toward leaf margin and continue in jagged manner parallel and close to the margin. Tertiary veining is offset pinnate. Veins are weakly depressed above and strongly expressed below.

Inflorescences of Jerusalem artichoke, in late summer into fall, consist of composite flower heads at the ends of stems and branches. The first flower heads to reach anthesis on the main stem or floral branches are the terminal heads. By the time the terminal flower head of the main stem or a branch is in bloom, heads on floral branches are already close to bloom. Depending on habitat and colony density, a plant may produce from several to 15 or more heads over a month or more.

Jerusalem artichoke - Helianthus tuberosusPhoto 4: Flower head bud on this 7-foot tall plant terminates the main stem. Secondary stems, as can be seen growing from leaf axils, will quickly also produce flower heads.

Flower heads, varying from 2½ to 4 inches wide with a disk varying from 3/8 to 5/8 inch wide, consist of 12 to 20 infertile ray florets and 50 or more fertile bisexual disk florets. Ray florets have a strap-like, yellow, pleated ligule with a rounded tip. Yellow, ¼ inch long disk florets are tubular with five flared lobes. Stamens of disk florets have dark anthers, connate to each other and arranged in columnar fashion around the style. Styles have a long, split (bifurcated) stigma whose branches coil backwards. Florets are set on a convex receptacle supported by a rounded involucre comprising about 30 overlapping, lanceolate-triangular phyllaries in several series. Phyllaries, slightly darker than the peduncles, have short pubescence, similar to that of the peduncles. Lower portions of phyllaries are appressed while long tapering ascending tips are flared to reflexed. In cross-section, the flower head is round. Peduncles, subtended by small leafy bracts, have the same appearance as their supporting stem or branch, including short pubescence.

Jerusalem artichoke - Helianthus tuberosusPhoto 5: Long, mostly leafless floral stalks terminate with a single flower head. Scabrous stems and branches may be purplish. Photo in mid-September.

Jerusalem artichoke - Helianthus tuberosusPhoto 6: Styles of disk florets become exserted above the dark anthers. Stigmas divide and coil backwards.

Jerusalem artichoke - Helianthus tuberosusPhoto 7: Phyllaries in several series form the involucre. Wide lower portions of phyllaries are appressed while long tapering tips are flared to reflexed.

Fertilized disk florets produce ¼ inch long, flattened, grayish achenes (dry one-seeded indehiscent fruits) tipped with two small quickly-dropped bristles. The principal source of reproduction is vegetatively via the tubers.

Jerusalem artichoke - Helianthus tuberosusPhoto 8: In this early November photo, with flower heads drying, large leaves (upper and lower surface shown) are about to drop while leaves on small axillary stems remain green. Achenes shown in inset. (A potter wasp [Eumenes sp.] built an urn of mud for one of its offspring on underside of large leaf on right.)

For a garden or natural area with mesic soil, Jerusalem artichoke, with its tall large-leafed stems and showy flowers, would be striking. However, stems may need to be staked and chemical control may be needed to prevent aggressive spreading by tubers. Tubers, high in dietary fibers (inulin) and minerals, may be eaten raw or variously cooked.

In addition to Jerusalem artichoke, 15 other types of Helianthus (sunflowers) occur in Arkansas. Jerusalem artichoke has characteristics that may cause it to be incorrectly identified as one of three woodland sunflowers (Helianthus strumosus, Helianthus divaricatus and Helianthus hirsutus). Jerusalem artichoke, typically found in more moist sites, tends to be a stouter and larger plant with larger stem leaves that have longer petioles. Tubers, found on Jerusalem artichoke in fall and winter, do not occur on the three woodland sunflowers. For articles regarding the woodland sunflowers, see here and here.

  • Jerusalem artichoke, a native of North America, was an important food for Native Americans and early colonists. It was introduced to Europe where it became widely used for human and livestock food. The “Jerusalem” moniker is believed to be a corruption of the Italian word for “sunflower” (girasole, pronounced “jeer-uh-so-lay”). Jerusalem artichoke is not a true artichoke (Cynara cardunculus var. scolymus), but its tubers are said to have an artichoke flavor.

Article and photographs by ANPS member Sid Vogelpohl

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Know Your Natives – American Holly

Posted on December 6, 2017 by ANPS Webmaster

American holly (Ilex opaca var. opaca*) of the Holly (Aquifoliaceae) family is a broad-leaf evergreen tree frequently used for Christmas decorations. In the U.S., it occurs from Texas to Illinois east to Massachusetts and thence south and east to the Atlantic and Gulf Coasts. The genus name comes from scientific name for holm oak (Quercus ilex), which has broad evergreen leaves. The specific epithet “opaca” is a Latin word meaning dull or opaque (referring to the leaves), not glossy or transparent, in contrast to European species. In Arkansas, American holly is found throughout much of roughly the southeastern two-thirds of the state. In its native habitat it is found mainly in the understory of hardwoods and pines in moist, well-drained soils of rich lowlands, stream terraces, on northern slopes and along swamp margins. Other common names include Christmas holly, white holly (for its wood color), and evergreen holly.

American holly may reach 40 to 50 feet tall and, occasionally, taller**. Trees generally have a straight central trunk 1 to 3 feet in diameter, with several main branches in mid to upper portion. New spring branches, straight and slender, with minute short pubescence, are green at first, becoming light gray at the end of the growing season and, thereafter, a darker gray with lighter, often silvery blotches. With short, stout, stiff and crooked branches with similar growth rate along its entire height, trees are typically pyramidal with a rounded top. Young trees in full sun, which have branches to the ground, tend to be compact and densely branched while those in more shady settings have fewer branches and a more open structure. With age, lower portions of trunks becomes branch-free and upper branching becomes more open. Trunks have thin, gray bark that is usually smooth. Growth rate varies from slow to moderate, depending on habitat quality. American holly can survive Arkansas’s harshest winters, but does not survive fire or long-term soggy soils.

American Holly - Ilex opaca var. opacaPhoto 1: Thin bark may be smooth or rough. Trunk diameter of a young tree at left is 5 inches while diameter of tree on right is 1 foot 9 inches.

American holly has evergreen leaves that appear in early spring and drop off two springs later, about a month after new leaves have appeared. New spring leaves are a bronzy green that quickly changes to a medium green. Mature leaves have a slightly shiny upper dark green surface and a dull yellowish green lower surface. Leaves, alternate and elliptical in general outline, have thick stiff blades that range from 2 to 4 inches long and half as wide. Leaves bow-up from mid-rib to blade margins so that the blade is an elongated “bowl” (top convex and bottom concave), with a slightly billowy blade surface between secondary veins. The blade is stout enough that when the upper surface is pressed down, it springs back to its original shape. Blade margins typically have straight, sharp, stout, well-spaced, outward-pointing, sixteenth-inch, light-colored spines, along with an equally-sized spine at leaf apex. When spines are present, 3 to 6 pairs typically mirror across mid-rib. Narrowly revolute (turned under) leaf margins are wavy, when seen from above, with a spine tipping each wave. Bases of leaves are rounded to wedge-shaped. Petioles are relatively short at about ½ inch long on four-inch-long leaves. Upper mid-rib is boldly channeled and light colored while the mid-rib of lower surface is prominently exserted and light colored. Secondary, closely-spaced pinnate veins are obscure.

American Holly - Ilex opaca var. opacaPhoto 2: In spring, bronzy leaves grow from new green branches while dark green leaves from previous spring remain on gray branches. Yellowing leaves in background, about to drop, grew two years earlier. Photo taken mid-April.

American holly is dioecious (female and male flowers on separate trees). Female flowers typically occur singly on pedicels, but in groups mostly below terminal leaves of new twig growth. Fragrant male flowers occur in cymes comprising up to eight flowers, often in elongate clusters, from axils of current or previous years’ leaves or directly from current year’s stems. Inflorescences growing directly from new stems are subtended by elongate, weak bracts that quickly drop. Female and male flowers, of about the same size (¼ inch diameter), have four equally sized, spreading, white petals with cupped-tips. Female or pistillate flowers have four white infertile stamens positioned around a prominent ovary, while male or staminate flowers have four fertile stamens positioned around a small rudimentary pistil. Anthers of female flowers are tipped with a flattened white flange. Fertile oblong anthers of male flowers, bearing yellow pollen, face inward (introrse). Stamens of male and female flowers are positioned between the petals. Barrel-shaped bright green ovaries of female flowers have large, round, flattened, convex, yellow-green and sessile (no styles) stigmas. Petals are set in a small, pale green, four-lobed, persistent calyx.

American Holly - Ilex opaca var. opacaPhoto 3: These male flower buds, in cymes or cymose clusters, grow from old leaf axils, from new leaf axils, or directly from new stems. Leaves in the inflorescence typically have few spines. Photo taken late April.

American Holly - Ilex opaca var. opacaPhoto 4: Female flowers typically grow singly on pedicels but in groups positioned mostly below terminal leaves of new twig growth. Infertile stamens are tipped with an infertile flange. Photo taken first of May.

American Holly - Ilex opaca var. opacaPhoto 5: Display shows pistillate (female) inflorescence on left and staminate (male) inflorescence on right. Note infertile stamens of female flowers and infertile ovary of male flower.

Female trees produce round to slightly oblong, berry-like fruits (drupes) on short spindly stalks attached directly to branches. Immature green fruits mature to a low-gloss red (occasionally yellow) in November. Showy mature, firm fruits, ¼+ inch in diameter, contain four to six nutlets grouped into a circular shape, like the sections of citrus fruits. Red (or yellow) skin of fruit encloses dry yellowish pulp. Relatively small, persistent, four-sided calyxes are set tight against the fruit. The surface of light-tannish, three-sided (one rounded side and two flats sides) nutlets have longitudinal ridges. Fruit remains on trees through winter, unless eaten by birds. Nutlets are dispersed by local and migrating birds and small mammals.

American Holly - Ilex opaca var. opacaPhoto 6: Display of upper and lower leaf surfaces and fruits. Remnants of calyxes persist at base of fruits as a small yellowish square. Note obscure secondary pinnate veins and small terminal bud. Photo taken mid-December.  Inset shows occasional yellow fruit.

With its outstanding winter characteristics (green leaves and red fruit), American holly is often planted in the home landscape. When sufficient space allows for a large tree and its spiny leaves would not be a problem, the tree should be welcomed in a natural area or woodland garden. As broadleaf evergreens, both male and female trees are great winter accent plants, especially showy on a snowy day. Fruits are an important winter food for many song and game birds and small mammals. For a “clean” trunk, lower limbs may need to be removed.

American Holly - Ilex opaca var. opacaPhoto 7: Mature trees in home landscapes.

  • A second variety of American holly, native to the U.S., is Shrub or Dune Holly (Ilex opaca var. arenicola). It occurs in dry sandy sites in Florida.

** Arkansas’s Champion Tree, in White County, is 63 feet tall with a diameter of more than 4 feet.

Article and photographs by ANPS member Sid Vogelpohl

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Know Your Natives – Rusty Blackhaw

Posted on November 27, 2017 by ANPS Webmaster

Rusty blackhaw (Viburnum rufidulum) of the Arrow-wood (Adoxaceae) family, formerly of the Honeysuckle (Caprifoliaceae) family, is a small deciduous tree or large shrub (referred to as “tree” herein) with a year-round attractive appearance. It occurs in the U.S. from Texas to Kansas to Ohio to Virginia and thence into states along Atlantic and Gulf coasts. In Arkansas, it occurs statewide. Viburnum is the classical Latin name for this group of plants. The specific epithet means “rusty colored” in reference to the buds and leaf pubescence. Other common names include southern blackhaw, rusty nannyberry and blue haw. It grows in a wide variety of well drained soils in upland sites ranging from open woods and woodland edges to fence rows.

Rusty blackhaw reaches 15 to 25 feet tall, the taller trees growing in well drained, mesic soils. Plants usually have a single, low-limbed trunk to 6 inches in diameter, but may produce suckers that result in tight groves. New branches in spring originate either immediately above the previous year’s leaf scars or as adventitious buds that “sprout” on upper sides of older branches. New branches have pairs of lateral leaves that are evenly spaced and off-set 90 degrees from pair to pair. In a branch’s second growth year, new short and stout lateral branches (twigs) grow perpendicularly to the parent branch from axillary buds immediately above leaf scars. Branches have thin, smooth, gray bark at the end of their first growth year and later roughen and develop darker raised and irregular lenticels (pores). As upper branches age over a number of years, they become arched and the crown becomes rounded to irregular. The trunk and lower portion of vigorous branches, as they increase in girth, become vertically and horizontally fissured, creating a blocky appearance. Branches and trunks are round in cross-section.

Rusty blackhaw - Viburnum rufidulumPhoto 1: Branch on right has bark with early fissuring and small, rough lenticels. Trunk on left, 3 inches in diameter, has fissured, blocky bark.

In late fall, current and past year’s branches have apical and lateral buds. Larger apical buds (to ¼ inch long) project directly out from branch tips while smaller lateral buds are pressed against the branch. Buds have several pairs of rusty-colored scales (each pair offset 90 degrees) that meet edge-to-edge (valvate). The outer pair of scales has very short, velvety, rusty-colored pubescence while underlying pairs are less velvety. Apical buds have a flattened spear shape; larger apical buds with a truncated base enclose rudimentary flowers.

Simple, leathery, opposite leaves, up to 3+ inches long and 2½ inches wide, are mostly oval to obovate, but some at ends of branches may be elliptical. Petioles are short (to ½ inch) with flat to grooved upper surfaces. Petioles angle upward, but leaf blades twist toward the horizontal for best sun angle. Leaves in sunnier sites are more leathery and have a dark green and glossy upper surface and a lighter green lower surface. Leaf margins of trees in sunnier sites are jaggedly serrated and may be crinkled, while in shady sites, serrations are smaller and leaves are thinner. Leaf blades may extend a short distance down petioles. Venation, depressed on the upper surface, is pinnate with secondary veins disappearing before reaching leaf margin. Tertiary veins form a rectangular-pattern. Early in the growth year, rusty pubescence may be found on the petiole and underside of the leaf, especially along central and secondary veins. In fall, leaves display various shades of pink, red and purple.

Rusty blackhaw - Viburnum rufidulumPhoto 2: Upper stem resulted from current year’s growth while lower stem-segment exhibits four years of growth. Larger buds enclose rudimentary flowers. Shape of larger leaves, as shown, is typical while smaller elliptical leaves, as shown, are near ends of branches and twigs.

Rusty blackhaw is at peak-bloom by the first of spring when new leaves are fully unfurled. Inflorescence consists of convex cymes of closely spaced white flowers in clusters on a half dozen or so green, upright floral branches, which are also branched. Cymes, even occurring on shrubbier plants, are abundant and well spread over exterior of the tree. A cyme, to 5 inches across, may have 150 or more flowers that reach anthesis at the same time.

Rusty blackhaw - Viburnum rufidulumPhoto 3: In mid-April, cymes are positioned above new leaves. Leaves have a shiny surface and reddish petioles.

Flowers, ¼ inch across, are bisexual with a white corolla that has five broadly-rounded and widely-flared lobes. Five stamens, alternating between lobes, have white to translucent slender filaments bearing pale yellow two-part loosely attached anthers. Pale yellow stubby ovaries are topped by a short thick style and a flat stigma.

Rusty blackhaw - Viburnum rufidulumPhoto 4: Flowers have white corollas with five spreading lobes, exserted anthers and a stubby ovary.

In late summer, cymes have a short (¼ inch) woody base topped by 1½ inch long floral branches which have become reddish and droop due to fruit load. A few to a dozen or more fruits typically are produced on a cyme. Fruits are rounded-elongate (½ inch long and ¼ wide), glabrous (hairless), fleshy drupes, each with a single stone. Drupes, at first a light to medium green, become pale red before turning blue and then a shiny blue-black that is dulled by light blue haze (a waxy “bloom”). Juicy purple pulp of mature drupes becomes mealy as drupes wrinkle at final maturity. Fruit is persistent into early winter.

Rusty blackhaw - Viburnum rufidulumPhoto 5: With fertilization, ovary enlarges to a round-elongate fruit. Photo – late May.

Stones (3/8 inch long by ¼ inch wide) have a flattened, oval shape with a small point at one end. One side has a raised longitudinal middle section while the other side has a corresponding sunken section. Stones cleaned of pulp remain a dark blue color; however, true stone color is a medium tan.

Rusty blackhaw - Viburnum rufidulumPhoto 6: In fall, fruit changes from pale red to blue-black with light blue waxy haze (bloom). Floral branches become red. Photo – early November.

For a garden or natural area, rusty blackhaw is an excellent choice. It would do well in a rocky area in full sun to partial sun. A long-lived small tree with attractive leaves, plants produce a large number of white cymes in early spring and a striking, colorful display in fall. In winter, it exhibits interesting structure. Lower limbs may need to be removed to form a clean trunk for a tree and, if suckers appear, they may be removed. The fruit is also an excellent food source for birds and small mammals.

At least nine other members of the genus are found in Arkansas. The Arkansas species that most closely resembles rusty blackhaw is blackhaw (Viburnum prunifolium) which has very similar structural, flowering and fruiting characteristics, but tends to favor moist valley soils in the Interior Highlands (primarily in the Ozarks and Boston Mountains, but also with scattered occurrences in the Ouachitas). Leaves of Viburnum prunifolium tend to be thinner and more elongate, with smaller marginal serrations and pointed apices–somewhat plum-like. Rusty blackhaw can be identified by its rusty colored winter buds, mostly oval to obovate leathery leaves, shiny upper leaf surface and early rusty pubescence on leaves.

Article and photographs by ANPS member Sid Vogelpohl

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Know Your Natives – Drummond’s Aster

Posted on November 16, 2017 by ANPS Webmaster

Drummond’s aster (Symphyotrichum drummondii) of the Aster (Asteraceae) family is a herbaceous perennial with disk flowers that change color with age. Preferred habitats are partially sunny upland sites in open deciduous woodlands and woodland borders along streams and roads. This aster occurs from Texas and Alabama north to Minnesota and Pennsylvania. In Arkansas, one of 21 native asters in the genus Symphyotrichum in the state, Drummond’s aster occurs throughout the Interior Highlands and Crowley’s Ridge along with several additional scattered counties. The genus name comes from Greek words relating to “a growing together” and “hair,” based on a misconception that pappus hairs occurred in a ring in the type species, New York aster (Symphyotrichum novi-belgii). The specific epithet and common name recognizes Thomas Drummond, a Scottish botanist, who, in the early 1830s, collected specimens in Texas. Other common names include blue wood aster and hairy heart-leaf aster.

Young plants have a half-dozen or so round to oval leaves up to 2 inches long in a loose rosette. Leaves have long petioles with a central depression and with stiff ascending edges. Margins are boldly serrated. Upper surfaces are medium green and lower surfaces are lighter green. Soft dense pubescence covers the undersides of leaves while pubescence on the upper sides and along petioles is less soft and less dense.

Older plants develop new basal growth in late fall that survives into spring when plants may have one or a dozen or more terete stems in a tight clump (cespitose). Basal leaves, broadly lanceolate, form a dense mass from which stems bolt. Stems, which may reach 3 to 4 feet tall, have numerous short (6 inches) to long (18 inches) branches in the upper half as well as lower insignificant axillary branching. Stems are spindly and erect, but may lean when supporting a large inflorescence. Stems are light green in spring, possibly with purplish shading, becoming yellow-green in fall. Basal and lower cauline leaves wither as stems mature. Dead, brown, woody-like stems persist into the next growing season.

Drummond's Aster - Symphyotrichum drummondiiPhoto 1: In mid-April, multiple leafy stems of Drummond’s aster bolt from a tight root clump. Plant in lower right foreground is false aloe (Manfreda virginica).

Alternate, long petioled cauline leaves may be spaced 3 inches apart lower on stems with spacing gradually decreasing to 1 inch at base of inflorescence. Largest leaves occur in the lower half of plants where leaves may be 4 inches long and 1+ inches wide. Lower leaves have cordate bases and acuminate (long tapering) apices while higher leaves, with similar apices, have bases that become more rounded. Petioles, to 2 inches long, have narrow wings extending from leaf blade to petiole base that enhance central grooves along the petioles. Petiole and blade mid-rib form a gentle continuous arch (viewed from side), while cordate bases of leaves rise above that arch. Leaf axils below the inflorecence often produce groups (fascicles) of two or three small (to ¾ inch long and 3/8 wide) oblong to elliptic leaves with short, winged petioles. While large leaves have well-spaced shallow serrations or crenulations, margins of small leaves tend to have hardly perceptible serrations. Leaves, medium green above and lighter green below, may become a golden green late in the growing season. Lower leaf surfaces are uniformly covered by short, dense and soft pubescence, while upper surfaces have short, stiffer and less dense pubescence. Lower surfaces feel smooth; upper surfaces are slightly rough. Venation is pinnate with veins on the upper side slightly depressed and those on underside slightly expressed. Leaves within the inflorescence become increasingly smaller and narrower, with those that subtend peduncles and pedicels becoming lance shaped.

Drummond's Aster - Symphyotrichum drummondiiPhoto 2: Short dense pubescence can be seen on underside of a leaf (lower center right) and along stem and petiole (upper center). Petiole and leaf mid-rib form a gentle arch.

Drummond's Aster - Symphyotrichum drummondiiPhoto 3: Display of large cauline leaves and small axillary leaves. Upper leaf surfaces shown to left and lower surfaces to right of spindly lower stem section. Petioles of these cauline leaves are winged, regardless of leaf size. Photo: mid-October.

In mid-summer, floral branching occurs in upper portion of stems with first flowers appearing about mid-September. Inflorescences consist of a few to numerous long (6 inches), straight, spreading yet upward-trending lateral branches in open-spike style or short (2 inches) branches in a more compact panicle style. Branches have small bract-like leaves spaced ¼ inch or so apart along their entire length with uppermost leaves subtending peduncles from one to 4 inches long. Peduncles are lined with overlapping to closely spaced 1/16 inch lanceolate, ascending bracts which continue to the short pedicels from which bracts transition directly into lanceolate, pointed phyllaries. Composite flower heads, to ½ inch wide, are borne on the pedicels at and near peduncle apices. Additional minor flowering may occur directly from axils of the large cauline leaves where single peduncles bear flower heads along their upper ends. Flowering occurs in late summer into mid-fall.

Drummond's Aster - Symphyotrichum drummondiiPhoto 4: Prior to appearance of flowers, peduncles and pedicels, covered with pointed ascending bracts, appear cedar-like. Photo: early September.

Drummond's Aster - Symphyotrichum drummondiiPhoto 5: Plant at full bloom with long branches that create an open-spike style of inflorescence, as compared to a plant with short branches that would have a panicle style inflorescence.

Drummond’s aster, as with all asters in the genus Symphyotrichum, has composite flower heads consisting of seed-producing pistillate (no stamens) ray florets that surround seed-producing perfect (stamens and pistil) disk florets. Heads have 10 to 15 ray florets and a smaller number of tightly clustered disk florets.

Ray florets have narrow, white to blue ligules with rounded to slightly notched tips and claw-like (narrowed) bases. Ligules, about ¼ inch long and 1/16 inch wide, are arranged irregularly and may overlap. Short styles are topped by long, bifurcated and widely spread stigmas. Disk florets, 1/10 inch long, are tubular, with corolla tubes topped by triangular lobes which close the tube in bud but point upward at anthesis. Corollas are initially cream-yellow color, but become reddish purplish shortly after opening. Five elongate anthers, not exserted, form an erect unit that encircles a tannish style. Styles become strongly exserted and stigmas divide but remain joined at their tips. Flower heads have a flat center (receptacle) held by an involucre composed of imbricated (overlapping), lanceolate, appressed and glabrous sepal-like phyllaries. Phyllaries may have a purple tip. Color differences along phyllaries may create a subtle diamond-shaped pattern. Phyllaries, in 4 or 5 series, transition directly into the lanceolate bracts that extend down the pedicel and onto the peduncle. Inferior ovaries are topped by bristly structures (pappus).

Drummond's Aster - Symphyotrichum drummondiiPhoto 6: Corollas of disk florets change from cream-yellow to reddish-purple as florets mature. Note similar appearance of appressed phyllaries and bracts. Photo: mid-October.

Drummond's Aster - Symphyotrichum drummondiiPhoto 7: A flower spike bearing heads at various stages of bloom. Note white bifurcated stigmas of pistillate ray florets (see floret at upper-right corner). Apices of phyllaries may be purple (see left-most flower heads).

Each ray and disk floret may produce a single brown achene (technically called a cypsela–a dry one-seeded, non-splitting fruit from an inferior ovary) with tufts of white hairs (pappus) encircling the top. Achenes, about 1/10 inch long, are oblong and ridged. They are dispersed by wind.

Another blue-flowered aster species of Arkansas that has disk flowers that change from yellow to purplish, and grows in similar habitats as Drummond’s aster, is blue wood aster or heart-leaf aster (Symphyotrichum cordifolium). S. cordifolium has leaf blades that have an overall heart-shape (not just the base) and long, unwinged petioles. Leaves of Drummond’s aster have shorter winged petioles.

Article and photographs by ANPS member Sid Vogelpohl

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Know Your Natives – Blue Sage

Posted on November 2, 2017 by ANPS Webmaster

Blue sage (Salvia azurea var. grandiflora) of the Mint (Lamiaceae) family is a long lived herbaceous perennial with sky-blue flowers. Variety grandiflora occurs throughout a large portion of the central U.S. stretching from Utah to Ohio, and from South Dakota and Michigan to New Mexico and Alabama. The typic variety, var. azurea, occurs farther to the southeast from Mississippi to Florida to North Carolina.  In Arkansas, var. grandiflora occurs throughout the Highlands that compose the Ozark Plateaus, Arkansas Valley and Ouachita Mountains, as well as in higher elevations of the West Gulf Coastal Plain. Blue sage is primarily found in well-drained, dry to mesic, and sandy to rocky soils of sunny prairies, open woodlands, roadsides and glades. Salvia, meaning “healer”, is the old Latin name for sage, based on some plants of the genus having possible medicinal properties. The specific epithet refers to its blue flower color. Other common names include Pitcher* blue sage and wild blue salvia.

Plants have long, slender and sturdy upright to leaning stems that reach 2 to 5 feet tall. The number of stems increases over the years so that rough, knobby, compact clumps form with a multitude of long, tough and slender, radiating to deeply bedded roots. Early stems have short dense pubescence, but this pubescence may be worn away as the season progresses. Branches, most numerous in the upper portion of plants, grow singly from axils of opposite leaves. Although length of branches varies, in general, lower branches may be 14 inches long with length gradually decreasing toward the plant apex, where lengths may be less than an inch. Long branches may have secondary branches. Plants are drought tolerant; however, leaves wilt during hot dry periods, and flower development is interrupted. Stems and branches are four-sided with broadly rounded corners made prominent by deep central grooves along the faces. Stems have a purplish cast in spring, change to medium green in summer and become yellowish in fall with lower stems changing to brown, as the epidermis splits with growth and stems become rounded. Woody dead stems persist into the next growing year.

Blue sage - Salvia azureaPhoto 1: In mid-April, purplish stems are densely pubescent.

Growth scars encircle stems and branches at base of petioles so that stems and branches are uniformly divided into 1 to 2-inch segments. Segment length remains fairly uniform all along stems and branches while stem diameter decreases slightly at upper ends of segments. Growth scars, which are purplish in mid-season, become brown in fall.

Blue sage - Salvia azureaPhoto 2: In mid-May, this leafy multi-stemmed plant has not yet attained a height where stems branch. Growth scars, around stems at petiole bases, are purplish.

Cauline leaves (there are no basal leaves) grow from grooves along opposite flat sides of stem, with leaf pairs rotated 90 degrees from pair to pair. While lower leaves may be four inches or more long and ¾ inch wide, upper stem leaves below the inflorescence may be an inch or less long and ⅛ inch wide. Leaves within the inflorescence become increasingly smaller to tiny and bract-like and tend to drop off in dry periods as flowering continues. Leaves are linear-lanceolate with very gentle tapers to blunt-tipped apexes and wedge-shaped (cuneate) bases. The taper to the leaf base is so gentle that separation of leaf blade from its short petiole is not especially discernable. Leaves have widely-spaced, shallow serrations which are clearly seen on large leaves but become obscure to absent on smaller leaves. Upper leaf surface is a medium grayish-green with a slight gloss while the lower surface is the same color with lower gloss and a lighter colored, raised midrib. Leaf blades, in-folded along midveins, feel coarse. Crushed leaves have a light, non-minty scent. Later in the growing season and especially when soils dry in hot weather, lower leaves drop off.

Inflorescences consist of terminal spikes on main stems and axillary branches, regardless of length. Flowers occur in paired opposite clusters of two to twelve tightly packed flowers on 1/16-inch weak pedicels. Larger paired clusters appear to be whorled about stem (false whorls or verticillasters). Lower paired clusters may be an inch or more from each other, but up-spike separation may decrease to the extent that the upper portion of spikes appear to be “solid” with flowers, although separation is still present. Although flowering occurs generally from lower to upper portions of floral spikes, flowers within a cluster mature at varying times so that total bloom period may extend from mid-summer to mid-fall as spike tips continue to grow. Flowers are larger at first-bloom while temperatures are cooler and soil moisture remains uniform.

Flowers, ½ to 1 inch long, have mostly sky-blue corollas each with an upper and lower lip (bilabiate). A large, fan-shaped and glabrous (hairless) lower lip has a v-shaped notch in its central outer margin and a long tight slit in its side margins resulting in four lobes; two large lobes in front and two considerably smaller proximal lobes. Upper and lower lips join to form a narrow throat that extends into a gray-green tubular calyx covered with short pubescence. The entrance to throat (and nectar) is tight. The softly pubescent upper lip is rolled into an upright, elongate, rounded, hump-backed and close-topped ¼-inch tube that has an imperceptible slit along its length, facing the flower center. The floral throat and central portion of the lower lip are smudged or streaked with white; the lower side of the lower lip is mostly whitish. The calyx, about ¼ length of corolla, has three triangular points, with an upper broader point at the top of calyx and the other two points along the calyx’s sides. The calyx, with weak longitudinal ridges, is flattened from top to bottom with a corresponding flattening of the floral throat.

Blue sage - Salvia azureaPhoto 3: First flowers blooming in early September. Note that opposite clusters of flowers are subtended by small, linear, leaf-like bracts. Also note ridged calyxes.

Blue sage - Salvia azureaPhoto 4: In late September, plants appear straggly. Many calyxes are gaping open after flowers have faded and nutlets are being dispersed.

Flowers of blue sage, with only two anther-bearing stamens, have a unique, elaborate architecture that helps ensure efficient deposit of pollen onto pollinators. Side-by-side stamens extend into the throat and upper, hooded lip of the corolla. In most flowers, and even in most mints, an anther (typically at the tip of a stamen) comprises two half-anthers (each with pollen sacs) that are closely adjacent to each other, with a thin strip of tissue between them called the connective. In blue sage, and in many other species of Salvia, that connective expands into two arms, pushing apart the two half-anthers: A fertile (pollen-bearing) half-anther is projected forward and lodged under the hood of the upper lip, while a sterile half-anther (the half-anther itself is actually so reduced that only the connective remains–see photo 5) is projected back into the throat of the corolla tube. This bizarre anther (and there are two of them in each flower) with its aberrant connective is delicately hinged onto the tip of the staminal filament and becomes a kind of see-saw. When a large bee enters the throat of a flower in search of nectar at the base of the corolla tube, the bee’s head pushes up against the two sterile connectives, causing the two fertile half-anthers to see-saw down and deposit pollen on the top of the bee’s head or thorax.

A blue sage flower’s pistil, too, is designed for pollination by large bees. The stigma becomes receptive after the flower has shed its own pollen (greatly reducing self-pollination and promoting cross-pollination). The style extends into the corolla’s upper lip, slightly past the anthers, where it is divided into two stigma lobes: a longer thinner fish-hook-shaped portion and a shorter stouter prong-shaped portion. The fish-hook portion is angled toward the back of the upper lip while the prong portion is exserted through the slit of the hooded upper lip. With this disposition, the stigma is well positioned to intercept pollen from the bee’s head and thorax.

Blue sage - Salvia azureaPhoto 5: Two complete flowers (#1 [upside down] and #2 [right-side up, and showing hooded upper lip nicely) and a divided flower (#3 to #8): upper hooded lip (#3), stamen pair (#4 [fertile half-anthers are to the left, sterile half-anthers to the right]), unequally divided style (#5), lower fan-shaped lip (#6), lobed ovary (#7), calyx (#8), and nutlets (#9).

So let’s review the elaborate pollination mechanism of blue sage, with its interesting “working relationship” with large bees. Bees land on large lower lip and thrust themselves head-first into flower’s throat to reach nectar. The bee’s head pushes against the sterile ends of the connectives so that the fertile half-anthers see-saw down from the ceiling of the upper lip. If pollen has not already been shed, “concave” anthers (perfect match to shape of bee’s head) deposit pollen onto the hairy head. When a pollen-bearing bee then visits a flower that is receptive to pollen (prong-portion of stigma exserted), pollen can be transferred to that flower’s pistil. (Fish-hook portion of stigma may also become exserted, but is typically not positioned to take pollen directly off a bee.)

Blue sage - Salvia azureaPhoto 6: Display showing lower lip of a flower with stamen pair (on left) and see-saw structure of a stamen pair with divided style (on right). Note that (on right) pollen is present on “concave” anthers, but divided stigma is not yet fully developed.

Blue sage - Salvia azureaPhoto 7: While this bumble bee (Bombus bimaculatus) gathers nectar, the prong portion of the stigma takes pollen from its head while the thinner portion extends outward at tip of hooded upper lip. Note unequal portions of divided stigma and pollen mass collected by bee.

A fertilized ovary may produce several 1-seeded nutlets. Nutlets mature quickly after fertilization and may drop from calyxes while calyxes are still green. The ⅛-long nutlets are light tan with a rough exterior.

When established in a garden or naturalized area, blue sage reliably returns year after year. Its straggly appearance at maturity can be improved by removing half of its upper growth in late spring. Plants need consistent moisture to look their best, but a wilted plant will renew flowering when conditions improve. Removal of winter-dead stems improves plants’ appearance in spring.

Other native species of the genus that occur in Arkansas are: lyre-leaf sage or cancer-weed (Salvia lyrata) and lance-leaf sage (Salvia reflexa). Lyre-leaf sage, occurring statewide, is a short perennial with blue flowers and deeply cut basal leaves. Lance-leaf sage, reported from a couple of northern counties, is an annual with overall characteristics similar to blue sage, except plants are shorter, leaves wider, flowers smaller and ridges on calyxes more prominent. Non-native scarlet sage (Salvia coccinea), reported from Pulaski County, has heart-shaped leaves and scarlet flowers.

  • Named for Zina Pitcher, a 19th-century doctor and amateur botanist.

Article and photographs by ANPS member Sid Vogelpohl

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Know Your Natives – Palafoxia

Posted on October 24, 2017 by

Palafoxia (Palafoxia callosa) of the Asteraceae (Aster or Composite) family is a drought tolerant annual herb. The genus name recognizes José de Palafox y Melzi (1776–1847), a Spanish officer in the war against Napeoleon. The specific epithet is derived from the Latin for “hardened,” from the tips of the bracteal leaves (phyllaries) that subtend the flower heads. In the U.S., palafoxia occurs in Texas, Oklahoma, Missouri, Arkansas, and purportedly in Louisiana and Mississippi. In Arkansas, this species occurs in the northern most counties of the Ozark Plateaus and Crowley’s Ridge. It is the only species of the genus in the state. Another common name is small palafoxia, as compared to a larger southwestern U.S. desert species (Palafoxia arida). Habitats include dry to well-drained sunny sites with rocky soils derived from limestones or sandstones in glades and on gravel bars and along roadsides.

Palafoxia has slender, erect stems that grow 16 to 24 inches tall with multiple intertwining branches. New stem growth is a pale green with lower stem portions becoming light to dark tan and hardened with age. Stems and branches, terete in cross-section, have very short, slightly scarbrous pubescence which transitions into more noticeable dense, flat-topped and viscid glands within the inflorescence. Plants have mostly alternate leaves and branches, but lower leaves and branches are opposite. Although plants produce many fairly long leaves, due to their shape, the plants have an open and airy appearance.

Palafoxia - Palafoxia callosaPhoto 1: This palafoxia plant in mid-June shows characteristic slender, erect stems and early branching.

Palafoxia - Palafoxia callosaPhoto 2: Palafoxia in early September approaching full bloom. The plant is growing on a rocky slope among the stems of hidden dropseed (Sporobolus clandestinus).

Linear to acicular leaves may have blades 3 inches long and ⅛ inch wide with an ⅛ inch long petiole. The very narrow leaves, widest at mid-leaf, slowly taper toward petiole and leaf apex. The leaf apex is acuminate with a blunt white tip. Leaves are medium green above and light green below and are up-folded along the mid-vein. Other than the mid-vein, which is strongly expressed on the lower side, other venation is not noticeable. Upper and lower leaf surfaces are covered with very short, rough hairs so that both surfaces feel slightly scabrous. Leaf margins are entire (untoothed). Upper leaves become increasingly short to less than an inch long and then tiny within the inflorescence.

Palafoxia - Palafoxia callosaPhoto 3: Leaves grow from stems covered with very short pubescence. Two typical leaves displayed at bottom show underside (lower leaf) and upper side as well as their short petioles. Note blunt white leaf tips.

Inflorescences consist of two to four solitary flower heads on ½ to ¾ inch long peduncles in one to several loose panicles at ends of slender, erect floral branches. When at full bloom in late summer, hundreds of flower heads cover plants growing in favorable sites. Floral branches are densely covered by stubby, glandular and viscid hairs that trap small insects, such as aphids.

Palafoxia - Palafoxia callosaPhoto 4: Stems are multi-branched with branches being almost indistinguishable from the main stem. In this display, stems favor one side of main stem due to having grown on a steep slope.

Flower heads are discoid, composed of 15 or more disk florets (all tubular). Florets of each head bloom in close succession, seemingly in unison. Their rose-pink color in bud changes to lighter pink shades as they bloom and fade. Flowering of a plant is mostly completed in a week or so. A floret has five 3/16 inch-long linear-elliptic lobes that join to form a short (1/16 inch long) tube that has a red ring just below the lobes. Heads are subtended by an involucre composed of six to eight elongate, light green, 1/8 inch long linear phyllaries. Each phyllary is longitudinally in-folded so that involucres have a ridged, turbinate (inverted cone) shape. Purple anthers are adnate one to another, forming a ring about the style. White pollen is produced at ends of anthers before a floret’s style emerges from within the anther column. Anthers are attached to rose-pink filaments which are longitudinally bent when a floret initially opens, but the filaments straighten as anthers (and encircled style) become exserted. After anthers of a floret have dispersed their pollen, the rose-pink style becomes exserted above the anther column and the stigma becomes bifurcated to expose long, narrow stigmatic surfaces that arch gracefully outward as they sharply curve under. (Palafoxia is a protandrous plant–pollen of a floret is removed or dispersed before the stigma becomes receptive.)

Palafoxia - Palafoxia callosaPhoto 5: Discoid flower heads reach maturity in close succession. Bent filaments, as seen in upper right floret of flower head on left, straighten as anthers and style become exserted. Note glandular pubescence along peduncles at upper left.

Like all composites, the florets’ ovaries and fruits are inferior: the corolla tubes with their attached stamens are set on the top of dark gray, flat-topped, conical fruits that have an upper end with four sides and a lower portion that is rounded to a blunt point. The top of each fruit (fruit type is an achene, like the common sunflower “seed”) is ringed by a very short tuft of whitish hairs (pappus). Fruit length, including pappus, is about ⅛ inch long.

Palafoxia - Palafoxia callosaPhoto 6: Display of a separated discoid flower head. Note slender corolla tubes topped by a red ring, exserted bifurcated stigmas, and developing seeds with pappus fringes.

Palafoxia would be a good selection for a well-drained sunny garden or natural area that may have rocky soil. A healthy specimen of this annual species produces a large number of small rose-pink flower heads that are interesting at a distance or close-up. A free-seeding species, it may grow in large numbers. Flowers attract butterflies.

Palafoxia - Palafoxia callosaPhoto 7: Panicle in upper right includes florets with exserted anthers bearing white pollen (right side and lower side) as well as florets with developing achenes (left side). Butterfly is a checkered skipper (Pyrgus communis).

Article and photographs by ANPS member Sid Vogelpohl

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Know Your Natives – Yellow Leafcup

Posted on October 11, 2017 by

Yellow leafcup (Smallanthus uvedalius), formerly Polymnia uvedalia, of the Aster (Asteraceae) family is a tall herbaceous perennial with very large petiolate leaves. The genus name honors John Kunkel Small, American botanist and author of Manual of the Southeastern Flora, 1933–still the most recent comprehensive floristic treatment of the Southeast. The specific epithet is from Latin for “stands out”. In the U.S., it is found from central Texas to southeastern Kansas to Michigan to New York, thence southward to the Atlantic and Gulf Coasts. In Arkansas, it is found statewide. Yellow leafcup is the only species of the genus Smallanthus occurring in North America. Other common names include bear’s-foot and hairy leafcup. Its habitat includes moist soils in partially sunny thickets, woodlands and fields.

Yellow leafcup - Smallanthus uvedaliusPhoto 1: In this late February photo, new stems arise from a clump of tuberous roots. Previous year’s stem lies on the ground.

Yellow leafcup, when fully mature, routinely reaches 4 to 5 feet tall, but may be up to 10 feet tall. Roots are a tight clump of elongate, irregular fibrous to tuberous roots. The stout, round (terete), erect stems may have a lower-stem diameter of an inch or more. Main stems sparingly develop secondary stems which may be 4+ feet long. The hollow (fistulose) stems bear opposite decussate leaf pairs (rotated 90 degrees from each adjacent pair). Petioles of larger leaves widen at their bases such that stems have “rings” at those nodes. Short, cup-like or two-lobed, leafy cauline appendages (stipules) grow between the opposite petioles on these rings. Moving up-stem, the diameter of the stem noticeably reduces in cross-sectional size from one pair of leaves to the next, in telescoping fashion. Stems have three rounded, longitudinal ridges extending below petioles, but ridges are flattened along lower portions of larger stems. Stems, a light green color, are densely covered with uniformly short pubescence that varies from hirsute (bristly) lower on stems to puberulent (soft) within the inflorescence. Main and secondary stems, along their upper portions, bear floral branches (to 10 inches long) from axils of leaf pairs. In winter, dead stems break off at ground level where they continue to decay into the following year.

Yellow leafcup - Smallanthus uvedaliusPhoto 2: Stipules (leaf cups) grow from “rings” that connect petioles of opposite leaf pairs. Dense cauline pubescence extends onto petioles.

Leaves are variable in shape and size, but  all are thin and flimsy with very short hirsute pubescence across the upper surfaces and mainly along veins on lower surfaces. With denser pubescence on the upper surface, which is hooked toward the leaf apex, the upper surface feels softly scabrous (rough). The upper leaf surface is a medium green while the lower leaf surface is lighter green with the veins being lighter still. The unusual leaf venation comprises three major veins, two of which join the midvein above the base of the leaf blade. These three primary veins serve as midveins for the three large, irregular lobes. Veins of the upper surface are depressed and those of the lower surface are expressed.

Large lower cauline leaves, to 12+ inches long and 8+ inches wide, have two primary lateral lobes and a terminal lobe. These main lobes, ending with broadly tapering tips, have several secondary tips and irregular undulations, but otherwise margins are smooth. Although leaf blade tissue narrows abruptly below the lateral lobes, leaf tissue in the form of jagged “wings” often continues down the sides of the petiole, especially on larger and lower leaves, stopping an inch or so from the stem or extending to the stem. The upper surface of a petiole becomes deeply grooved toward the stem. Upper cauline leaves become smaller and less lobed to unlobed, with a tapered apex and a broad base above a winged petiole. Within the inflorescence, small broad leaves may have five spreading tips and short petioles, further reducing in size up-stem to linear and sessile.

Yellow leafcup - Smallanthus uvedaliusPhoto 3: Leaves decrease in size and become less complex up-stem. Small linear leaves occur within the inflorescence.

Yellow leafcup produces composite flower heads in mid to late summer that are positioned around the upper perimeter of the plant. Several uppermost cauline leaf pairs of main and secondary stems each produce two acutely-spread, axillary floral branches with or without a central branch. These lateral and central branches, depending on plant maturity and environmental factors, may bear additional opposite linear leaves which, in turn, support further stem division within the inflorescence. The “highest” or most distal cauline leaf pair subtends erect peduncles (stalks of inflorescences) to 1½ inches long that bear several clusters of flower heads on weak pedicels to ¾ inch long. Upper portions of stems/branches, peduncles and pedicles are equally covered with dense, fine pubescence.

Clusters of two to five flower heads occur in equally sized opposite pairs. Along with a terminal cluster, up to six or so lower opposite-branched pairs may occur in corymb-style arrays. Clusters and individual flower heads are subtended by small opposite linear leaves, except the terminal head does not have a subtending leaf. Flower heads and clusters tend to be crowded together. A multi-stemmed mature plant may produce several hundred flower heads.

Yellow leafcup - Smallanthus uvedaliusPhoto 4: Display shows a stem (or branch) that originally terminated with a single flower head (at lower center). A pair of floral branches grew from axils of the lower large leaves and another pair grew from axils of small linear leaves within the inflorescence.

The composite flower heads, to 2 inches wide and facing outward or downward, consist of up to a dozen yellow pistillate (fertile pistils but no stamens) ray florets and 50 or so staminate  (fertile stamens and infertile pistils) yellow disk florets based on a 1/4-inch wide receptacle. Elliptic pleated ligules of ray florets (to about 5/8 inch long), pinched at their bases, have two or three stubby apical lobes. Styles of ray florets with bifurcated stigmas are also yellow. Disk florets have flared corollas with five triangular lobes that join to form a stalked, skinny and campanulate (bell shaped) tube. Corollas of disk florets enclose a tube of five purple anthers that produce yellow pollen. The anther tube hides a white style with an undeveloped stigma, so that rudimentary ovules do not develop into seeds.

Yellow leafcup - Smallanthus uvedaliusPhoto 5: Flower heads shown are at various stages of development: a bud at lower right, heads at anthesis at lower left and upper right and a head with maturing fruit at upper left.

Flower heads have a convex receptacle from which florets and receptacular bracts grow. Each ray floret and disk floret is subtended by a bract positioned away from the center of the flower head. Bracts that subtend ray florets are broadly triangular with acute tips (3/8 inch long and 2/8 wide) and are cupped so that the ovaries and developing fruits are tightly enveloped. Bracts subtending ray florets, also triangular, are smaller and narrower. Four to six leafy, triangular and longitudinally pleated involucral bracts (5/8 inch long and ½ wide), which loosely covered the flower head while in bud, subtend flower heads. The pubescence of receptacular and involucral bracts is not noticeable without magnification.

Yellow leafcup - Smallanthus uvedaliusPhoto 6: Display of a divided flower head along with two separated disk florets. Note convex receptacle, purple anthers topped with pollen and large ovules of ray florets. Note subtending receptacular and involucral bracts.

With fertilization, ray florets produce hard, slightly flattened, ovoid achenes. Achenes, about ¼ inch long and wide, are almost circular when viewed from a flattened side. The achenes are smooth and purplish to dark brown.

Article and photographs by ANPS member Sid Vogelpohl

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Know Your Natives – White Leafcup

Posted on September 19, 2017 by

White leafcup (Polymnia canadensis) of the Aster (Asteraceae) Family is a coarse,  short-lived perennial. The genus name is in reference to the Greek Muse Polymnia (also spelled Polyhymnia), goddess of music, song and dance. The specific epithet refers to the plant’s occurrence in Canada. In the U.S., its greatest concentration occurs in eastern Oklahoma across Arkansas and Missouri and, from there, scattered north into Minnesota to Vermont as well as south into northern Alabama. In Arkansas, it is primarily limited to the Interior Highlands (Ozark Mountains, Arkansas River Valley and Ouachita Mountains). Other common names include small-flower leafcup, white-flower leafcup, white bear’s-foot and Canadian leafcup*. White leafcup’s habitat preference is light to medium shade in consistently moist, well-drained, rocky deciduous woods, ravines and talus slopes.

White leafcup is an herbaceous plant with several stems from 2 to 5 feet long that grow from short fibrous roots. Plants are mostly erect and may have a few lower branches along with shorter branching in the inflorescence. Lower branches grow straight from the main stems at a wide angles. Terete stems and branches are fistulose (hollow) and larger stems have noticeably longitudinal, rounded ridges. Stems and branches vary from light green to purplish with light green dominating on younger portions of branches and along shady sides of smaller stems and branches. Stems and branches are puberulent (covered with fine short down) throughout the plant, with pubescence within the inflorescence becoming longer and glandular (sap at hair tips). The glandular pubescence causes upper portions of flowering branches to feel viscid (sticky). Leaves are opposite or the uppermost alternate. Leaf margins are narrowly turned-under (revolute).

Lower leaves, to 12 inches long and 8 inches wide, have two to four somewhat opposite deeply cut lobe pairs with irregularly large-scale serrated margins. The terminal lobe, lateral lobes and major secondary lobes have acuminate (gradually tapering) tips. The largest lobes may be 2½ inches long and 1 inch wide. The soft leaves, dull light to medium green on upper and lower surfaces, are puberulent on the upper surfaces and less so on lower surfaces. The upper half of the petioles have wings with the same characteristics as the leaf lobes, including irregular margins. Wings lower on the petioles/midribs are narrower. Petioles, to 4 inches long and rounded with flat tops, have short pubescence with longer scattered hairs along their edges. Pinnate venation is slightly suppressed on upper surface and strongly expressed on lower surface, with lower midrib of larger leaves standing in sharp, rounded relief. Crushed leaves have a strong lemony scent.

White Leaf Cup - Polymnia canadensisPhoto 1: A young plant bearing the characteristic large ragged leaves of the species. Photo in mid-June

The bases of opposite leaves may be expanded and fused so that they wrap around the stem to form a leafy cup (the basis of the common name “leafcup”).

Leaves up-stem into the inflorescence become smaller, with shapes varying from hastate to broadly triangular. These small leaves may have entire (undivided) margins or shallowly crenulated margins with tiny tips that mark ends of tertiary veins. Smaller leaves do not have expanded bases and petioles are not winged.

White Leaf Cup - Polymnia canadensisPhoto 2: Display showing large and smaller leaves and upper and lower surfaces. Small leaves at top have crenulated margins with tips. Note ribbed stem, purplish coloration and barely expanded leaf bases.

Flowering, consisting of composite flower heads, may occur from late spring into mid-fall over a two month period. Upper portion of branches bear several clusters of flower heads. Clusters are subtended, going from those lower to upper in the inflorescence, by small hastate leaves, to smaller triangular leaves, to even smaller lanceolate leaves and to tiny bract-like leaves. Each flower head in a cluster (except for terminal flower heads) is subtended by a short linear bract about ⅜ inch long and 1/16 inch wide. Flower heads are on weak pedicels to about ¼ inch long. Terminal flower heads of a cluster bloom first.

White Leaf Cup - Polymnia canadensisPhoto 3: Stem and branches topped by clusters of flowerheads. Stems tend to be purplish.

White Leaf Cup - Polymnia canadensisPhoto 4: In a shady open site, branches are especially long and low-angled. Some leaves and branches are opposite and some are alternate.

Buds of the flower heads are covered by involucral bracts (phyllaries) in two series, the inner slightly longer than the outer. Margins of phyllaries bear long, twisty and sticky hairs (viscid pilose pubescence). As florets mature, apices of phyllaries curve backward.

When the disk of the flower head is first exposed, its flat surface is covered by light green, pointed, elongate-triangular and concave bracts, which individually wrap around each disk and ray floret. Ray florets develop ligules that extend outward. Each disk floret opens directly upward. The first florets to reach anthesis are ray florets along with the outermost ring of disk florets followed incrementally by smaller rings toward the center of flower head. The width of flower head when ray florets are at anthesis is up to 1¼ inches. The round involucres are about ⅓ inch deep and wide.

White Leaf Cup - Polymnia canadensisPhoto 5: Pubescence of branch, phyllaries and floral bracts can be seen. Note ligules just beginning to show on bud at upper left and leaf shapes of cluster on right.

Flower heads bear up to a dozen pistillate (no stamens) ray flowers and 25 or more light yellow staminate (pistils not functional) disk flowers. Ray florets have obovate, white ligules with pleated surfaces and three equal-size shallow, apical lobes and pubescent pinched bases. Ligules, about ⅓ inch long and broad, are sharply bent at their bases so that ligules flare outward. Styles of the ray florets are white with white bifurcated stigmas. Disk florets have pale yellowish-green flared corollas with five triangular lobes that join to form a skinny stalked tube. Corollas of disk florets enclose an exserted column of five light yellow stamens with yellow pollen. The column of stamens encircles a style with an infertile stigma based on a rudimentary ovary with ovules that do not develop.

White Leaf Cup - Polymnia canadensisPhoto 6: Staminate disk florets produce pollen while pistillate ray florets bear bifurcated styles.

White Leaf Cup - Polymnia canadensisPhoto 7: Display showing parts of a flower head that held eight pistillate ray florets, receptacular bracts that subtended the ray florets, two involucral bracts and a few staminate disk florets.

With fertilization, a flower head produces hard brown ovoid achenes. Achenes are about ⅛ inch long with rounded bases and three-angled apexes.

A second species of the Polymnia genus occurs in Arkansas, namely Cossatot leafcup (Polymnia cossatotensis). This species, endemic to Arkansas (five known sites in Polk and Montgomery Counties), is found on novaculite talus slopes. This annual species has heart-shaped leaves and flower heads with relatively small yellow centers of disk florets and usually two to three white ligules.

Peruvian daisy or quick weed (Galinsoga quadriradiata), recorded from seven scattered Arkansas counties, has flower heads similar in appearance to those of white leafcup. This non-native invasive species is a much smaller plant with coarsely toothed but unlobed leaves and occurs in open, disturbed areas.

  • The terms “small-flower” and “white bear’s-foot” are in contrast to structures in the closely related bear’s-foot or yellow leafcup (Smallanthus uvedalius), previously classified in the Polymnia genus. Bear’s-foot, a larger plant than white leafcup, has larger yellow flowers and broader leaves and is most often encountered on stream and river terraces.

Article and photographs by ANPS member Sid Vogelpohl

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