Hairy woodland sunflower (Helianthus hirsutus), of the Sunflower, Aster, or Composite (Asteraceae) family, is one of three Arkansas species with the common name “woodland sunflower.” The genus name is based on Greek words for “sun” and “flower.” The specific epithet is Latin for “hairy” or “bristly.” In the U.S., hairy woodland sunflower occurs from the Florida panhandle west to east-central Texas and north to the Carolinas, Ohio, and Minnesota. The species also occurs in south-central Canada and mountainous areas of central Mexico. In Arkansas, occurrence is statewide. Habitats include woodland edges, savannas, and prairies in loamy to rocky, moist to dry soils. Other common names are bristly sunflower and stiff-haired sunflower.
Hairy woodland sunflower bears near-surface, narrow, ropy, white rhizomes (underground stems). New plants develop at rhizome tips while the established rootstock continues to produce annual stems, so that colonies form quickly.
This herbaceous perennial produces erect to leaning, rigid stems to 5+ feet tall with opposite, decussate (alternating 90 degrees) leaf pairs. Petiole bases join around the stem as a slight ridge. Stems are densely covered with coarse, bristly hairs. Branching is limited to one to several opposite pairs of short axillary floral branches along the uppermost length of stems. A mature stem may have 10 to 20 pairs of larger leaves below the floral branches, separated by 3 to 4 inch internodes. Overwintering dead stems persist into the new year.
Typical leaves below the floral branches are broadly lanceolate, about 6 inches long (including petioles) and 1¾+ inches wide, with shallowly serrate margins. Like the stems, they are hirsute (coarsely hairy). Petioles, stout and pubescent, decrease in length from stem base (¾ inch) to stem apex (1/16 inch). Leaves have three primary veins: the midrib and a pair of laterals.
The inflorescence, occurring for a month or more in mid- to late summer, consists of one to a half dozen or more composite flower heads per stem. Flower heads terminate the main stem as well as the stem-like peduncles (½-2 inches long) of lateral branches.
Flowerheads, 2+ inches across, are set in a bowl-shaped involucre which may be from ½ to 1 inch wide. Flower heads have 10 to 16 sterile ray florets which surround up to 90 or so fertile florets in the central disk. Involucres comprise 20 or so phyllaries (bracts) in three to four imbricated series. The ¼+ inch phyllaries are lanceolate, narrowing to sharp, ascending to revolute tips.
Ray and disk florets are a bright yellow with the ray florets remaining at anthesis as the disk florets bloom in sequence centripetally (from the outermost disk florets into the center of the disk). Ray florets have elongate petal-like corollas (ligules) to ¾ inch long, somewhat ridged longitudinally. Disc florets are each subtended by light yellow, chaffy, receptacular bracts. The 1/4-inch-long tubular disk floret corollas have 5 stubby triangular lobes; the 5 stamens have purplish anthers, fused into a ring. At anthesis, the style emerges through the exserted ring of anthers, carrying with it their yellow pollen, which is now available to pollinators. The stamens then shrink back into the corolla, and the style divides to expose two elongate, recurved stigmatic surfaces.
The perfect disk florets (with stamens and pistils) have, like all composites, inferior ovaries. With fertilization, ovaries harden into dry, narrowly ovoid, 1-seeded fruits (achenes) about ⅛ inch long, with a pair of loosely attached awns at their apex. These are the familiar “sunflower seeds.”
Hairy woodland sunflower is well suited for a larger native plant garden where this tall, leaning plant with its rather aggressive colonizing nature can be accommodated. It is an important fall and winter food source for wildlife, including butterflies, moths, birds, and small mammals. Long-dead stems can be removed for a more tidy spring garden.
Fifteen additional species and subspecies of sunflowers (Helianthus) occur in Arkansas. Of these, two other woodland sunflowers, H. strumosus and H. divaricatus may become confused with H. hirsutus. All three are widespread in the state, with similar growth habits and habitats. With close examination, H. hirsutus may be distinguished from the other two species by morphology of the involucre and degree of pubescence (see links immediately above). Another species that may become confused with the woodland sunflowers is Jerusaleum artichoke (H. tuberosus). Hybridization among the three woodland sunflowers makes an already difficult determination even harder.
Article and photographs by ANPS member Sid Vogelpohl
EDIT 9-14-2020 – We reach our goal of $1,000! Thank you to all who contributed!
The Ozark Society Foundation (OSF) is requesting support from the Arkansas Native Plant Society for the design and printing of a new publication, Trees, Shrubs, and Woody Vines of Arkansas. OSF is requesting financial support to address a portion of the graphic design expenses.
The book will be over 400 pages, containing photographs, illustrations and maps to identify woody flora of Arkansas. The completed book will be designed as a field guide for outdoor use and as a reference volume for schools, libraries, and individuals.
Book production will be completed in winter 2020. At that time, OSF will promote the book, conduct public events, and provide for sales and distribution. Revenue from sales will advance the conservation work of OSF and the Ozark Society. Both are Arkansas-Incorporated, 501(c)(3) nonprofit organizations.
The new book will be more comprehensive and relevant than any previous work on the subject. It will include descriptions of over 400 woody plants as well as up-to-date information on species names, ranges, and habitat. The book will include updated county-level distribution maps, 16 plates of botanical illustrations and more than 1,500 full-color photos.
The book will appeal to numerous institutions with interest in an Arkansas field guide. Interest in the book will be strong in public education, ecology, and natural sciences. Conservation professionals, including botanists, foresters, and land managers, would use the book as a field or desk reference. Outdoor enthusiasts, hikers, hunters, and amateur botanists, and their membership organizations are also highly interested in the topic.
The book was created for OSF by co-authors University of Arkansas, Fayetteville botanist Jennifer Ogle, Arkansas Natural Heritage Commission ecologist Theo Witsell, and University of Arkansas, Fayetteville professor emeritus Johnnie Gentry. The authors coordinated with botanists, ecologists, artists, and photographers to develop the book content, including University of Arkansas at Monticello professor emeritus Eric Sundell, who reviewed the manuscript, the late Linda Ellis, who drew the botanical illustrations, and ANHC contractor Molly Robinson, who obtained photo use permissions and developed a visual key for the book.
OSF has published high-quality books on Arkansas conservation issues for more than thirty years. The work leading up to Trees, Shrubs, and Woody Vines of Arkansas started in 2012. The project initially focused on revising a previously published OSF book, a field guide to state trees, shrubs, and vines authored by Carl Hunter. Because Hunter’s original photos were unavailable and more contemporary materials were accessible, OSF chose to create a new field guide. Until recently, project progress was delayed by organizational transition, professional relocation, and the death of individuals. OSF is again actively coordinating the project with the co-authors and publishing industry businesses. In 2020, book design, printing, and distribution will be implemented.
OSF is requesting financial support of $1,000 from the Arkansas Native Plant Society to address a portion of the graphic design expenses. ANPS support will be recognized in the book and in all promotional materials and media descriptions.
Additional Support is being requested from:
Arkansas Game and Fish Foundation Arkansas Forestry Commission Department of Arkansas Heritage Arkansas Game and Fish Commission Arkansas Master Naturalists
Pawpaw (Asimina triloba) of the Custard Apple (Annonaceae) family is a small deciduous understory tree with edible fruit. It is widespread in the deciduous forests of the eastern U.S., from eastern Texas and southeastern Nebraska, east across southern Michigan to the Atlantic Coast from Pennsylvania to northern Florida. In Arkansas it occurs statewide. The genus name is based on the Native American name “assimin.” The specific epithet refers to the number of petals and sepals. The common name “pawpaw” was first used by the English in the 16th century for papaya (Caricapapaya) and later used by early American settlers for this species. Along with various spellings of pawpaw, other common names include Arkansas banana, wild banana, custard apple, and banango. Habitats include deep, mesic, sandy to clayey soils of rich, shaded bottomlands, floodplains, ravines, and slopes. Pawpaws have deep taproots with shallow runners that produce nearby clonal sprouts. Trees have slender and branch-free lower trunks. Mature trees are typically from 15 to 20 feet tall, but may reach 40 feet.
Leaves and branches are alternate, in two opposing rows, however this arrangement becomes less noticeable as some branches and twigs become dominant while others die away. Short reddish pubescence on new branches is lost as they age and become glabrous. New bark is yellowish green before becoming reddish brown to gray during the first year. Bark of mature trunks is thin, gray to gray-brown, with lighter splotches, corky lenticels (air pores), and minimal fissuring.
In late March into mid-April, single flowers emerge from rounded lateral buds along year-old branches. In mid-winter, the dark fuzzy flower buds are knobby. With anthesis approaching, they become yellowish green before changing to deep reddish brown to purple. First flowers tend to open before leaves appear, but then leaf growth and flower progression continues simultaneously for about a month.
Flowers, about 1½ inches across, are pendulous, with three sepals, and a veiny corolla of three larger outer petals and three smaller inner petals, both whorls a striking maroon to reddish brown. Pedicels and sepals are covered by a dense reddish brown pubescence. Flowers have a somewhat fetid scent which attracts pollinating flies.
Flowers have an elongate receptacle bearing a dense mass of numerous stamens surrounding a cluster of 3-6 separate pistils. The stamens have stubby filaments topped with tightly packed, pale yellow anthers that en mass create a brain-like surface. Pistils consist of elongate ovaries, with short styles and rounded yellowish stigmas. After anthesis, stamens disintegrate as the receptacle shrinks to eventually form a “ring-collar” at the base of the fruit.
Leaves emerge after flowers have begun to bloom. Short, reddish pubescence is lost with leaf maturity. Simple oblanceolate leaves grow to about 1 foot long and 3½ inches wide with ⅜-inch petioles. Margins are entire. Crushed leaves have a strong, distinctive scent, like green peppers––a useful field character.
Pollinated flowers may produce one or a cluster of several rounded to oblong fruits (large berries) 1-4 inches long. Fruits develop from bluish green to yellowish as they ripen and may weigh a half-pound or more. An isolated tree may produce fruit, but cross-pollination increases fruit production. The greenish pulp becomes white to yellow, soft, sweet, and delicious as the fruit matures. Fruits contain to about 10 dark brown, inch-long, smooth and shiny seeds in two rows. Peduncles, at fruit maturity, may be an inch or more long.
Pawpaws, with their large leaves, striking flowers, and delicious fruits, merit a special place in gardens and natural areas. They are easy to grow in partially sunny areas as well as, once established and with adequate moisture, sunny areas. Trees in sunnier areas will be less leggy and bear more flowers and fruit. The fruits have a banana-mango (?) flavor appreciated by many people. If a colony is not desired, clonal sprouts need to be removed annually. In early winter, those sprouts can be successfully transplanted with appropriate care (shading and watering). Leaves are not eaten by deer, but fruits are a favorite of deer, box turtles, raccoons, and other small mammals. Pawpaws are host plants for the Zebra Swallowtail (Protographium marcellus), Pawpaw Sphinx Moth (Dolba hyloeus), and the Asimina Webworm Moth* (Omphalocera munroei).
Dwarf pawpaw (Asimina parviflora), a species of conservation concern in Arkansas, is the only other species of the genus in Arkansas (Miller and Union Counties). Dwarf pawpaws are more shrub-like with significantly smaller but similar leaves, flowers, and fruit.
* Caterpillars of Asimina Webworm Moth bind terminal leaves into ugly wads of dead leaves. As long as the terminal buds are not damaged, branches continue normal growth the next spring.
Article and photographs by ANPS member Sid Vogelpohl
Woodland agrimony (Agrimonia rostellata) of the Rosaceae (Rose) family has leafy stems terminating with a raceme(s) of small yellow flowers. The genus name is a corruption of Argemone, the botanical name of the prickly poppy. The specific epithet is based on a Latin word for “beaks,” in reference to the fruit shape. In the U.S., the species occurs from eastern Texas to eastern Kansas in a broad sweep all the way to the eastern seaboard from South Carolina to Massachusetts. In Arkansas, it occurs statewide except for some portions of the Mississippi Alluvial Plain and the West Gulf Coastal Plain. Habitat preference is for partially sunny areas with well-drained, rich to sandy soils of mixed woodlands and woodland edges and openings. Plants are also called beaked agrimony.
The plant has a small caudex with long horizontally trending fibrous roots to 5 or more inches long and several long descending ropy roots of similar length. During summer months, the caudex produces large white buds which appear as new stems in late winter.
This herbaceous perennial, to 2½ feet tall, has one to several erect (sunny sites) to reclined (shady sites) sparsely pubescent stems. Alternate compound cauline (stem) leaves are distinctively odd pinnate, with one to three pairs of opposite primary (large) leaflets, a similar number of opposite secondary (much smaller) leaflets, and a primary terminal leaflet. Secondary leaflets occur as one or several pairs between the primary pairs and may also occur below the lowermost primary pair. Mid-stem primary leaves may be to 5 inches long and 4½ inches wide. All leaflets are sessile (the stalk of the terminal leaflet is the final segment of the rachis, not a petiole).
Leaves are glabrous above, while the lower leaf surface has sparse long hairs along the main veins and crowded, minute glandular pubescence between veins. Except for the smallest secondary leaflets, all leaflet margins are prominently dentate. Pairs of stipules subtending the leaves may be small and elliptical or larger––to 5/8 inch by 5/8 inch––recurving around the stem like wings. Paired leaflets and stipules are mirror images of each other. The sparse hairs that occur on stems extend onto the petioles and rachises.
The inflorescence, flowering primarily in July, comprises racemes that grow from the upper leaf axils. Total length of an inflorescence may be 1+ feet with individual racemes to 5 inches long. On a typical plant, stems transition apically into an unbranched raceme. On more robust plants, branched stems may produce several racemes which in turn may divide into secondary racemes. The erect to slightly twisty racemes bear up to 20 small, well-spaced flowers. The raceme rachis is covered with minute, stubby glandular hairs.
At anthesis, the solitary ascending flowers are about ¼ inch wide with 5 sepals, 5 petals, and 5-15 stamens attached at the rim of a densely bristly, cup-shaped hypanthium. Two pistils with superior ovaries are hidden in the hypanthium, their 2 erect light yellow styles emerging with star-shaped stigmas to the level of the anthers. The hypanthium and outer (lower) surface of the sepals are covered by minute glandular hairs. After blooming, petals and stamens quickly drop off and sepals reclose to cover the domed hypanthium.
The slightly nodding, ovoid fruits consist of the hypanthium with the persistent sepals reclosed across the hypanthium’s domed apex (forming the knob-like “beak”). The spiky protrusions present during flowering persist on the fruit as hardened, hooked bristles. Fruits attach to passing animals (and humans) for seed dispersal. Fruits, ⅛+ inch long and wide, contain 1-2 seeds.
In a shady to partially sunny garden or natural area, if this small deciduous perennial was interspersed with other leafy plants, it would hardly be noticed. However, as a specimen plant, it would present its interesting growth pattern and add an interesting leafy texture. Woodland agrimony does not seem to be an aggressive self-seeder and does not seem to be eaten by deer.
Three other species of the genus occur in Arkansas: low agrimony (A. microcarpa), southern agrimony (A. parviflora), and downy agrimony (A. pubescens). These species also have small yellow flowers in racemes and similar odd-pinnate leaves. Woodland agrimony can be distinguished by its 1) long straight cauline hairs, 2) ovate to elliptic leaflets that are mostly glabrous above and densely covered with minute glandular hairs beneath, and 3) fruits with a bowl-shaped lower half and bristles that are directed outward.
Article and photographs by ANPS member Sid Vogelpohl
White-nymph (Trepocarpus aethusae) of the Carrot (Apiaceae) family is the only species worldwide of the genus Trepocarpus––the genus is “monotypic.” Etymology of the generic name is uncertain. The specific epithet is a reference to Arethusa, a water nymph of Greek mythology. The species occurs in the central and southwestern portions of the Southeastern U.S., primarily from eastern Texas and Oklahoma to Alabama and Tennessee and north to southeastern Missouri, southern Illinois, and eastern Kentucky, with scattered occurrences in Georgia, Florida, and South Carolina. In Arkansas, it grows throughout most of the state except for portions of the Ozark Highlands. Habitats are moist to wet soils of lowland woods, floodplains, and swamp margins.
The herbaceous annual has a taproot to 2 inches long. First growth of a new plant appears during winter as a pair of long, grass-like cotyledons (seed leaves). The 2-3 foot tall mature plants bear alternate, highly dissected leaves on light green, finely ribbed, smooth and glabrous stems. Stem nodes are purple. Internodes zigzag from node to node. Crushed plant parts have a strong carrot odor.
The compound leaves are triangular in outline, the leaflets and sub-leaflets dissected into delicate lobes. Lower and mid-plant leaves are 3-times pinnate and uppermost leaves are 2-times pinnate. Petioles, about ¼ inch long, have winged upper edges and clasping bases. A large, mid-stem leaf may be 3½ inches long (including petiole) and 4 inches wide. Mid-stem leaves have several to eight or more opposite pairs of leaflets.
The inflorescence consists of compound umbels atop straight, leafless floral stems that are 2-4 inches long. Umbels consist of 3-4 umbellets that terminate straight ¼-½ inch long peduncles. Umbels and umbellets are subtended by several irregularly sized and positioned acicular bracts up to 1 inch long. Umbellets comprise 4-9 fertile and infertile flowers; pedicels of fertile flowers are very short (less than 1/16 inch) to absent while pedicels of the smaller infertile flowers may be ¼ inch long.
Fertile flowers, with spreading corollas slightly wider than 1/16 inch, have 5 minute acicular sepals, 5 petals, 5 stamens, and 1 pistil (consisting of an inferior ovary bearing 2 styles and stigmas). Floral parts are attached at the summit of a prominent naked ovary about ¼ inch long and 1/16 inch wide.
Umbellets produce several to half a dozen or more elongate fruits. As fruits mature in mid-summer, the entire plant quickly fades. Fruits, remaining as paired nutlets, persist on the dead branches as the plant disintegrates. Seed dispersal may be birds dropping a nutlet while removing chaff or by water-transport of the buoyant nutlets.
White-nymph, with lacy foliage and tiny white (nymph-like?) flowers, can be a lovely specimen plant, but can get lost among other plants. It can be an aggressive self-seeder and spreads easily in its preferred habitat. Spread can be controlled by removal of entire plants before seed dispersal. It may be suitable for a “controlled” area of a native plant garden or in a natural area. In midsummer, after seed-set, the plant quickly disintegrates. It is a host plant of the Black Swallowtail (Papilio polyxenes). It is not eaten by deer.
Although white-nymph is the only species of its genus, its structure is somewhat similar to that of several other species in the carrot family in Arkansas. It can be recognized by its intricately dissected, flattened leaves and white-petaled flowers atop large, glabrous ovaries.
Article and photographs by ANPS member Sid Vogelpohl
Snoutbean (Rhynchosia latifolia) of the bean or legume (Fabaceae) family is a perennial herbaceous plant with large trifoliate leaves. The genus name is from the Greek for “beak,” referring to the shape of the keel petals. The specific epithet is from the Latin for “broad leaves.” Snoutbean occurs from eastern Texas and Oklahoma, through southern Missouri, Arkansas, and Louisiana to western Tennessee and Mississippi. In Arkansas, it occurs across much of the state except for the Mississippi Alluvial Plain and Crowley’s Ridge. Habitats are sandy, partially shaded to sunny pinelands, savannas, and prairies.
Snoutbean has a woody, knobby, vertical root which may be a foot or more long. Current year’s stems grow from the roughened swollen crown at the soil surface.
Plants may have one to several, densely hairy, yellowish green stems, often with axillary branches along their lower portions. Initially erect, they become reclined and trailing, while the actively growing tips are twining. They grow to 4 feet long, supporting each other and sprawling against other vegetation.
Leaves are densely short-pubescent, alternate, and pinnately trifoliate (the terminal leaflet is stalked but the laterals are subsessile), with a pair of small, lanceolate stipules at the base of the petiole. The lowermost leaves are simple. Leaflets are broadly ovate-orbicular with rounded bases and sides. Larger leaves may be 5¼ inches long and 5½ inches wide, with a terminal leaflet 3 inches long and 1¾ inches wide and a pair of opposite lateral leaflets 2½ inches long and 2 inches wide. Leaf size gradually decreases distally.
The inflorescences consist of elevated, axillary racemes of up to 15 or more flowers along the upper portion of the stems. The densely short-pubescent calyx, less than a half inch long, consists of three broadly lanceolate free-standing sepals below the corolla and a fused pair of similarly shaped sepals above.
The bright yellow corolla is “papilionaceous,” a butterfly-like structure typical of many legumes, comprising a large, erect banner petal (flared laterally and apically) at the top, a free pair (not fused together) of smaller oblong wing petals projecting forward, and, within and below the wings, a pair of cupped-ovoid petals that together form a V-shaped keel. The wing petals (opening downward) form a hood over the keel (opening upward). The keel encloses 10 stamens with white filaments and light yellow anthers as well as a white pistil. Nine of the staminal filaments are fused into a tube, along their lower portion, which encloses the pistil. One filament, the uppermost, is free from the staminal tube. The pistil consists of a straight ovary tipped by a sharply up-turned style and terminal stigma. The corolla is about ½ inch long with a banner about ½ inch wide. The loosely attached wing and keel petals project ¼ inch beyond the banner. Flowers have short (less than ⅛ inch) pedicels. Flowering may extend over a month or more, primarily in June.
Fertilized ovaries develop into flattened green, densely pubescent pods which become dark brown at maturity. Pods, with persistent calyxes and short down-turned terminal beaks, are ½ to ¾ inch long and ¼ inch wide. They split from base to tip to release two irregularly rounded, smooth, shiny, dark brown seeds. Diameter of seeds is about ⅛ inch.
In considering snoutbean for a garden, with its deep roots and good seed germination, it is probably best suited for a natural area––it has a somewhat untidy growth habit. Large shamrock-shaped leaves and showy flowers make it a decorative and interesting plant. Snoutbean prefers sandy and rocky well-drained soil and partial to full sun. It is not eaten by deer.
At least two other species in the genus have been reported from Arkansas. Least snoutbean (Rhynchosia minima) has only been documented in Chicot County. It can be distinguished as a smaller plant with more rhombic leaflets, descending flowers, very short calyxes and curved pods. Double-form snoutbean (Rhynchosia difformis) may be widely scattered in central and southern Arkansas. It can be distinguished by its shorter, compact inflorescences and shorter calyxes.
Article and photographs by ANPS member Sid Vogelpohl
Most regrettably, due to the ongoing Covid-19 situation the ANPS Board has voted to cancel the Fall meeting slated for Stuttgart Sept. 18-20.
Scheduled field trips are also cancelled until Dec. 31, 2020.
We’re all quite sad that we have to miss another meeting with our native plant friends, but hopefully, come time for the spring meeting maybe we’ll all be pumped-up with Covid—19 antibodies from our Covid-19 vaccinations! How we’re hoping.
And other news is that the two students who had applied for the Delzie Demaree Research Grants were both approved by the membership, so hooray for them and we’re very proud of these students.
Other emails will be coming to you periodically, so know that we’re not signing off at all for the the next six months for there’s always something going on with ANPS, and you’re the biggest part of it!
Thanks for your understanding, and let’s all continue to remain vigilant.
Sundrops* (Oenothera fruticosa) of the Evening Primrose (Onagraceae) family has bright yellow flowers open during the day. The genus name may be from Latin (oenothera) for a sleep inducing plant or from Greek (onothera) a hypnotic plant added to wine. The specific epithet is based on Latin for “bushy”. In the U.S., the species occurs from eastern Oklahoma east to Florida and north to Michigan and New England. In Arkansas, it is primarily a species of the Interior Highlands. It is also known as narrow-leaf sundrops and southern sundrops. Habitats include dry to moist but well-drained, partially shady to sunny areas, such as open woodlands, woodland borders, and country road rights-of-way.
Plants, with shallow, fibrous, somewhat thickened roots, develop a flat-lying basal rosette of leaves over winter, followed by one to over a half dozen erect slender stems that grow 1-2 feet tall. Young stems and branches are reddish and pilose, with dense, soft, white pubescence. Older stems become tan, harden, and may lose their pubescence.
Stem leaves are mostly alternate, but may be opposite at the ends of branches and tightly clustered at and within the terminal inflorescence. Leaves have a blunt, rounded apex and a gradually tapering (acuminate) sessile base. Leaves are oblanceolate, those of the basal rosette to about 4 inches long and ¾ inch wide, the larger stem leaves to about 3½ inches long and ½ inch wide. Leaves are pilose on both surfaces, with hairs of the upper surface short, dense, and evenly spread, while hairs of the lower surface are concentrated along the midrib and leaf margins. Margins of smaller leaves are entire; those of larger leaves are obscurely wavy. Margins are revolute (turned under), especially on larger leaves.
The inflorescence consists of single flowers growing from leaf axils, each blooming for one day. More vigorous plants tend to have a tight, terminal cluster of leaves, producing a large and showy flower cluster. Below the terminal flowers, upper leaves may subtend a flowering branch. With inflorescences blooming sequentially, the flowering period, primarily in May, may extend for a month.
Flowers develop from cylindrical buds comprising 4 sepals, 4 petals, and 8 stamens attached atop a long, narrow, terete floral tube. The yellowish floral tube is attached to the summit of a pale green, thickened, “inferior” ovary (i.e., the ovary is below the insertion of the other flower parts). Here the club-shaped ovary is lined with eight ribs and tapers into a slender floral stalk, the pedicel. Sepals, floral tube, ovary, and pedicel are covered with long, soft, white hairs.
Sepals are partially fused to each other and retract from the petals, as the bud opens, either asymmetrically as a unit of four to one side of the flower or opposite each other in two pairs. Flowers have 4 large bright yellow petals, 8 yellow stamens, and a long yellow style. Petals are broadly rounded with an indented apex and translucent veins that serve as insect guides. Stamens have long delicate filaments to which slender anthers are attached in see-saw fashion, the better to accommodate contact with the pollinator, typically a lepidopteran. The slender style, extending from the ovary through and well beyond the floral tube, elevates the stigma above the anthers, where it divides into four widely spread receptive lobes. These showy, spectacular flowers may be to 2 inches across with a ¾ inch long floral tube and a ¾ inch long ovary.
After anthesis, flowers quickly drop from the ovary. With fertilization, the ovary matures to a hardened capsule about ¼ inch long with a stalk of similar length. When dry, capsules split along four seams from the top downward. The numerous seeds are tannish, smooth, and lopsided.
In a garden or natural area, this plant would be mostly unnoticed when not bloom. In bloom, it has striking yellow flowers. It is adaptable to various well drained soils and can do well in partial shade. In favorable sites, it may need to be managed to prevent excessive spreading by seed. It is eaten by deer.
Seventeen total species and/or subspecies of the genus Oenothera are known to occur in Arkansas. All except one of these have yellow flowers. The species most similar to O. fruticosa is O. pilosella (prairie sundrops), with two subspecies represented in the state. Oenothera pilosella differs from O. fruticosa by having shorter pedicels and thus nearly sessile capsules.
Day-blooming species of the genus are referred to as “sundrops”. Night-blooming species are referred to as “evening primroses.”
Article and photographs by ANPS member Sid Vogelpohl
Forest pea or bushy vetch (Lathyrus venosus) of the Bean or Legume (Fabaceae) family is a perennial deciduous vine with pea-like flowers. The genus name is based on the Greek Lathyros, the ancient name for a leguminous plant. The specific epithet is from the Latin for “conspicuously veined,” in reference to the banner, the large, uppermost petal of the legume flower. In the U.S., forest pea occurs primarily in three areas: 1) an area from far-east Texas and northwestern Louisiana to southern Missouri, 2) an area from the central Great Lakes region that extends westward into the eastern Dakotas northward to the Canadian border, and 3) an area along the Appalachian Mountains with a concentration in central Virginia and West Virginia. In Arkansas, the species occurs primarily in the Arkansas Valley, Ouachita Mountains, and higher elevations of the West Gulf Coastal Plain. Preferred habitat is moist to dry slopes in open deciduous woodlands.
Forest pea has shallow ropy rhizomes terminating with a knobby vegetative bud that produces new growth the following year. Fibrous roots are mostly limited to year-old rhizomes. Like most legumes, forest peas have a symbiotic relationship with bacteria which “fix” atmospheric nitrogen in root nodules, converting it to a form the plant can use.
Stems, to 2-3 feet long, are fairly stout and ascending; however, unless anchored by tendrils at the leaf tips, they lack the strength to remain upright and tend to sprawl. They are prominently angled and glabrous to finely pubescent. New stems appear in mid-winter.
Ovate to elliptic leaflets, to 2 inches long and ⅞ inch wide, are rounded at the base and narrowed to a blunt, sometimes mucronate (pin-point) tip. Margins are entire.
The inflorescence, in late March to early May, consists of a single erect raceme to 6 ½ inches long with 10-20+ closely spaced, pea-like flowers along the upper third of a slender peduncle. Racemes arise at the swollen leaf bases of several upper leaves. Flowers are about ⅝ inch long and ⅜ wide with a short pedicel.
The dangling flowers bear colorful, tubular calyxes (to ¼ inch long) with three larger acutely pointed lobes on the lower side and two smaller in-turned, pointed lobes on the upper side. The corolla exhibits the typical structure of the so-called papilionaceous flower of the legumes, comprising a large banner petal (flared laterally and apically), a free (unattached) pair of smaller wing petals, and a fused pair of keel petals. The projecting wing petals (opening downward) form a hood which encloses the beaked keel (opening upward). The keel encloses 10 stamens and a pistil, all well hidden. Nine of the staminal filaments are fused most of their length into a tube that encloses the pistil. One filament––the uppermost––is usually free from the staminal tube. The pistil (of a single carpel) comprises a greenish, elongate, straight, flattened ovary tipped by a sharply up-turned style which tapers to an elongate stigma. Flower color is a blending of pink and white with the banner more strongly colored and prominently veined.
With fertilization, long, flat, yellowish green pods develop to a mature length of about 3 inches. When mature and dry, pods dehisce and the smooth sides (valves) twist back to expose the seeds. The brown globoid seeds, up to a dozen per pod, are smooth with a lighter hilum. Seed dispersal by small mammals and birds.
Forest pea would be a good choice for a woodland garden or natural area, with its loose growing habit and leafy character. Flowers and fruits are interesting, but not especially showy. It is not aggressive by rhizomes or seed. It is also apparently not eaten by deer.
In Arkansas, other species of the genus are non-native yellow vetchling (L. aphaca), non-native singletary pea (L. hirsutus), non-native everlasting pea (L. latifolius), and the native yet uncommon low vetchling (L. pusillus). Forest pea is readily distinguishable from these species based on its large compound leaves which have five to seven pairs of leaflets and terminal tendrils. The prominent veins of the banner also distinguish the species.
Forest pea may be confused with species in the vetch (Vicia) genus (nine of which occur in the state). Flowers of Lathyrus species have free wing petals whereas wing petals of Vicia species are adnate (fused) to keel petals. Also, leaflets of Lathyrus species are larger than those of Vicia species.
Article and photographs by ANPS member Sid Vogelpohl