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  Fabaceae: Astragalus racemosus

  R Neil Reese

  Astragalus racemosus is a perennial herb growing from a branched caudex, with multiple, often branched, erect to ascending stems, 15-70 cm tall that are thinly to densely covered with appressed hairs. The alternate, compound odd-pinnate leaves are4-15 cm long, with short petioles below and sessile above, with stipules 3-12 mm long. there are 11-31 leaflets, 1-4 cm long, the lower leaves having broader lance-elliptic leaflets, and the upper leaves with narrower lanceolate leaflets. The inflorescence consist of axillary racemes with 15-70 papilionaceous flowers on peduncles 3-11 cm long. The flowers are generally nodding on pedicels 2-3.5 mm long. The calyx tube is covered in white, appressed hairs, .bell-shaped, 5-7 mm long, sometimes swollen at the base with 5 awn-like lobes, 2-10 mm long. the 5 petals are white to cream colored with purplish tips and or streaks. The banner is 6-12 mm long, the clawed (constricted at the base) wings 12-19 mm long, and the clawed keel 10-16 mm long. The fruit are triangularly compressed legumes, 3.5-7 cm long, 3-6 mm in diameter, with a stipe on the end that is up to 7 mm long. Alkali milkvetch blooms from May to July on poorer soils in prairies, plains, hillsides and in stream valleys in western South Dakota.

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  Fabaceae : Dalea aurea

  R. Neil Reese

  Dalea aurea is a perennial herb with 1 to several erect stems coming from a woody caudex atop a taproot and growing 20-75 cm in height. The stems are simple or branched above and covered with silky hairs. The petiolate leaves are alternate, compound odd-pinnate, blades 1-4 cm long, with 5-7 oblanceolate leaflets, 4-16 mm long. The leaves are largest toward the stem base and are reduced above. The inflorescence consists of silky-haired, many flowered, terminal cone-like spikes on the main stem and branches, becoming oblong-cylindrical, 1.5-7 cm long. The calyx tube is 2-3 mm long, with teeth 3.5-5 mm long and is densely covered with silky hairs. The corolla is papilionaceous, yellow, with all of the petals clawed (narrowed at the base). The petals above the claws measure as follows: banner 6.5-8.6 mm, wings 5-6 mm, and the keel 5.7-8.5 mm long. The fruit is a one-seeded legume, 3-4 mm long and covered with silky hairs. Golden prairie clover blooms from June into September in prairies, open hillsides, in ravines and in stream valleys in western and southwestern South Dakota.

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  Fabaceae : Dalea candida

  R. Neil Reese

  Dalea candida is a perennial herb with 1-several erect stems, simple or branching from above, growing from a caudex attached to a thick taproot, each stem 30 to 100 cm in height. The alternate, compound odd-pinnate, leaves are 1.5-6 cm long, with a short petiole, and 5-13 narrow, gland-dotted, light green leaflets, each 5-35 mm long. The inflorescence is a loose to dense cylindrical spike of flowers, 1.5-7.5 cm long, at the tip of each stem or stem branch. Each flower has a green calyx tube 1.9-2.7 mm long with teeth 0.6-1.8 mm long. The papilionaceous corollas have white clawed (narrowed at the base) petals that measure above the claws: banner 4-5.7 mm long, the wings and keel 3.2-5.3 mm long. The flowers at the base open first and the upper ones bloom later. The fruit is a green oval legume pod, 2.5-4.5 mm long, containing one seed. White prairie clover blooms from May to August on prairies, open woodlands and roadsides throughout South Dakota.

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  Fabaceae : Dalea enneandra

  R. Neil Reese

  Dalea enneandra is a perennial herb with 1-3 erect stems, branched above the middle, which are 5-10 dm tall and arise from a caudex attached to a yellow taproot. The alternate, nearly sessile, pinnately compound leaves are 1.3-2.6 cm long, with leaves on the main stem often deciduous by time of anthesis. The leaves 5-13 leaflets, narrowly oblanceolate, 4-12 mm long with black glands on the leaflets and midrib. The inflorescence consists of terminal, 2-ranked spikes, with 5-35 flowers, subtended by bracts, 3-4 mm long with pale or white membranous margins. The calyx tube is covered with silky hairs, 3-3.7 mm long with 5 teeth 3.3-4.6 mm long. The papilionaceous white petals are clawed (narrowed at the base) with the remainder of the petals measuring as follows: banner 5.7-7 mm, wings 2.8-4.1 mm, and the keel 5.5-7 mm long. There are 9 stamens. The fruit are one-seeded legumes, 3-4 mm long. Nine-anther prairie clover blooms in July and August in prairies, on hillside and in stream valleys in most of South Dakota.

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  Fabaceae : Dalea purpurea

  R. Neil Reese

  Dalea purpurea is a perennial herb, with ascending to prostrate stems, which grow singly or in groups from a woody caudex, 20 to 90 cm in height. The stems can vary from smooth to very hairy. The alternate, odd-pinnate compound leaves are 1.5-4.5 cm long, with 3-7 linear to linear-oblanceolate leaflets, 10-28 mm long and can be smooth to hairy. The inflorescence consists of terminal, conical, densely hairy spikes, 1-7 cm long attached to a peduncles 0-15 cm long. Each flower is subtended by hairy bracts, 2.5-5.8 mm long. The densely hairy, bell-shaped calyx tube is 2-3 mm long with teeth 1-2 mm long. The papilionaceous corolla has clawed (narrowed at the base), pinkish to rose to purple-colored petals with the petal length beyond the claws as follows: banner 4.5-7 mm, wing and keel 3-5 mm long. The fruit is a single-seeded legume, 2-2.5 mm long. Purple prairie clover blooms from May into August on prairies, hillsides, open woods and stream valleys throughout South Dakota.

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  Fabaceae: Desmodium canadense

  R. Neil Reese

  Desmodium canadense is a long-lived, perennial, herbaceous forb that develops from a stout, woody taproot. The plant typically reaches a mature height of 90 to 180 cm. Its central stem is erect, rigid, distinctively lined with vertical striations, and covered in an abundance of both fine hooked and spreading hairs, often branching exclusively within the upper half of the plant. Leaf insertion along the stem is alternate, supporting pinnately trifoliolate leaves. The medium-to-dark green leaflet blades are ovate to lanceolate with acute or obtuse tips and entire margins. Terminal leaflets measure 4 to 11 cm in length and 1.5 to 3 cm in width, which is noticeably larger than the lateral leaflets. The upper surface of the leaflet is sparsely puberulent to glabrescent, while the lower surface features a lighter pale-green coloration and is densely covered in fine, appressed hairs. Each compound leaf features a distinct petiole measuring 1 to 6 cm long. A pair of persistent, subulate-to-lanceolate, striate stipules measuring 4.5 to 10 mm in length is present at the base of the petiole. Flowering occurs from July through September. The inflorescence forms a dense, terminal, elongated panicle or raceme that can extend up to 40 cm long. The calyx consists of 5 fused sepals that are strongly bilabiate (two-lipped), measuring approximately 4 to 5 mm long, presenting a reddish-purple to green tint, and heavily blanketed in fine pubescence. The corolla is composed of 5 papilionaceous (pea-like), pink-to-rose or lavender-purple petals measuring about 1 to 1.3 cm long. The upright banner petal features a pair of prominent yellow spots at its inner base to act as a nectar guide, while the wing and keel petals are largely free but closely interlocked. Enclosed within the petals are 10 diadelphous stamens fused by their filaments into a 9+1 arrangement, which are translucent-white to light pink with tiny yellow anthers. A single, superior pistil features an elongated, green ovary about 5 to 7 mm long, tipped with a slender, curved style and a small, capitate, unlobed stigma. The fruit is a flat, dry loment measuring 1.5 to 3 cm in length, dividing into 3 to 6 segments (joints) that do not split open upon ripening. These pubescent, chain-like segments turn dark brown or greyish black at maturity between August and October, clinging tightly to passing animals or clothing. The Showy Tick-trefoil is native to South Dakota, where it occurs primarily across the eastern and central regions of the state in moist-to-mesic black soil prairies, river meadows, open thickets, lake borders, and disturbed roadside corridors.

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  Fabaceae : Glycyrrhiza lepidota

  R. Neil Reese

  Glycyrrhiza lepidota is a perennial herb arising from deep, woody, aromatic roots with multiple, erect stems, which grow 30-120 cm in height and are typically dotted with glands. The leaves are alternate, with petioles 5-50 mm long and stipules 3-7 mm long. The blades are compound odd-pinnate with oblong to lanceolate leaflets, 2-7 cm long with glandular dots, in groups of 7 to 21. The inflorescences are axial, dense, spike-like racemes of numerous flowers, with peduncles 1–6 cm long. The flowers have tubular-campanulate green calyx tubes that are 2-2.5 mm long, with teeth 2.5–3 mm long, the tube and teeth both having stalked glands. The papilionaceous corollas have white to yellowish white petals, the banner moderately erect, 10-14 mm long, keel and wings 8-12 mm long. There are 9 united stamens and 1 separate stamen. The fruit is an ellipsoid legume, 1–2 cm long going from green to orangish-brown with age and covered with hooked bristles 2–3 mm long. The fruit remain through the winter. American licorice blooms from July into September in prairie ravines, along streams and lakeshores and in other moist areas throughout South Dakota.

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  Fabaceae: Hylodesmum glutinosum

  R. Neil Reese

  Hylodesmum glutinosum is a perennial, herbaceous vine or sprawling plant in the Fabaceae family. It grows from a deep taproot and produces slender, sometimes hairy, trailing or climbing stems typically growing from 30 to 90 (140) cm tall. Leaves are alternate, trifoliate, with each leaflet ovate to elliptical, 3–7 cm long and 1.5–3 cm wide, with entire to slightly toothed margins. Each trifoliate leaf is attached to the stem by a petiole, with small, leaf-like stipules at the base of each leaf petiole. Leaflets are attached to the petiole by short stalks called petiolules. Flowering occurs mid to late summer (June–September). Flowers are pea-shaped, 1–1.5 cm long, purplish pink to lavender, appearing singly or in small clusters in leaf axils. The calyx has five sepals fused into a tubular base with five pointed lobes, 5 to 8 mm long and often glandular-hairy. The corolla consists of five petals typical of legumes: one large upright banner, two lateral wings, and two fused keel petals, ranging from 12 to 20 mm long. There are 10 stamens arranged in a diadelphous configuration; nine stamens are fused together into a tube surrounding the pistil, while one stamen remains free. The pistil is superior with a single carpel; the slender style curves upward to a small stigma. Fruits are legume pods measuring 3 to 6 cm long, slightly sticky or glandular, containing several seeds, and mature in summer to early fall. In South Dakota, large tick-trefoil is typically found in eastern and southeastern regions where habitats include open woodlands, prairies, thickets, streambanks, and sometimes along roadsides or disturbed areas.

  Synonym: Desmodium glutinosum

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  Fabaceae: Lotus corniculatus

  R. Neil Reese

  Lotus corniculatus is a perennial herbaceous legume that spreads by stolons and forms low mats or small clumps. Stems are slender, trailing or ascending, typically 10–50 cm long, and often glabrous or sparsely hairy. Leaves are alternate and compound, typically trifoliate with three leaflets measuring about 1 to 3 cm long and 0.5 to 1.5 cm wide; leaflets are obovate to elliptic with entire margins and smooth surfaces, sessile or have very short petiolules, about 5–20 mm long and 3–10 mm wide, with small stipules at the base of the leaf stalks. Flowering takes place from late spring through early fall (May–September). The inflorescence is an umbel-like cluster of 3 to 10 flowers. Flowers are bright yellow, sometimes with orange-red tinges on the petals, about 1 to 1.5 cm long, with a typical papilionaceous structure: a broad, rounded standard petal, two lateral wing petals, and a keel formed by two fused petals. Each flower is subtended by a calyx of five sepals fused at the base into a tubular cup about 5 to 8 mm long, with five pointed lobes that are lanceolate to ovate in shape and covered with fine hairs. Flowers have ten stamens, nine of which are fused, and a superior ovary. The fruit is a slender, curved pod about 2 to 4 cm long containing several seeds Bird’s-foot trefoil is native to Eurasia but widely naturalized and invasive in South Dakota, often found in pastures, roadsides, pastures, grasslands, and disturbed sites statewide.

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  Fabaceae: Lupinus argenteus

  R. Neil Reese

  Lupinus argenteus is a perennial herbaceous plant growing 30 to 90 cm tall. It has a fibrous root system with occasional short rhizomes but no stolons. The stems are erect, often covered with silvery, silky hairs giving the plant a grayish appearance. Leaves are alternate and palmately compound, typically with 7 to 11 narrow leaflets measuring about 2 to 5 cm long and 0.5 to 1 cm wide; leaflets are linear to lanceolate with entire margins and covered in fine silvery hairs. Leaf petioles are 5 to 15 cm long. The inflorescence is a dense raceme of pea-shaped flowers blooming from late spring to mid-summer (June–August). Each flower is subtended by a calyx of five sepals fused into a tubular structure about 6 to 10 mm long, with five pointed lobes that are ovate to lanceolate and densely covered with silvery hairs, each lobe measuring approximately 3 to 5 mm long and 1.5 to 3 mm wide. Flowers are typically blue to purple, about 10 to 15 mm long, with the classic papilionaceous form: the standard petal is broadly ovate and 8 to 12 mm long and 6 to 9 mm wide; the two wing petals are about 7 to 10 mm long and 3 to 5 mm wide; and the keel formed by two fused petals is about 7 to 11 mm long and 3 to 4 mm wide. Flowers have ten stamens, nine of which are fused, and a superior ovary. The fruit is a pod approximately 3 to 6 cm long containing several seeds. In South Dakota, Silvery lupine is native and found in dry open woods, meadows, and rocky slopes primarily in the western and Black Hills regions.

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  Fabaceae: Medicago lupulina

  R. Neil Reese

  Medicago lupulina is an annual or short-lived perennial herbaceous plant growing 10 to 50 cm tall. It has a fibrous root system with occasional short stolons allowing it to spread across the ground. The stems are slender, often sprawling or ascending, and glabrous to sparsely hairy. Leaves are alternate and trifoliate, with three oval to obovate leaflets measuring about 0.8 to 2.5 cm long and 0.5 to 1.5 cm wide; leaflets have entire or slightly serrated margins and smooth surfaces. Leaflets are sessile or have very short petiolules, and stipules are small and lanceolate at the base of the leaf stalks. The inflorescence is a small, dense raceme or head of 5 to 20 bright yellow, pea-shaped flowers blooming from late spring through summer (May–August). Each flower is subtended by a calyx of five sepals fused at the base into a tubular cup about 3 to 5 mm long, with five pointed lobes that are lanceolate and often hairy. Flowers are about 5 to 8 mm long. The corolla’s standard petal is broadly ovate, measuring approximately 5 to 7 mm long and 4 to 6 mm wide; the wing petals are about 4 to 6 mm long and 2 to 3 mm wide; and the keel, formed by two fused petals, is about 4 to 7 mm long and 1.5 to 3 mm wide. Flowers have ten stamens, nine of which are fused, and a superior ovary. Fruits are coiled, single-seeded pods resembling tiny spirals, maturing in late summer. Black medick is native to Eurasia but naturalized widely in North America, including South Dakota, often found in lawns, pastures, roadsides, and disturbed sites statewide.

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  Fabaceae: Medicago sativa

  R. Neil Reese

  Medicago sativa is a perennial herbaceous plant growing 30 to 100 cm tall, often forming dense stands. It has a deep, extensive taproot system that allows it to access deep soil moisture. The stems are erect to ascending, slender, and typically glabrous or sparsely hairy. Leaves are alternate and trifoliate, with three oval to oblong leaflets measuring about 1.5 to 4 cm long and 0.8 to 2 cm wide; leaflets have smooth or slightly serrated margins and a fine, soft pubescence on the surface. Leaflets are petiolulate with short stalks about 2 to 5 mm long, and stipules are small and lanceolate at the base of the leaf stalks. The inflorescence is a raceme or spike-like cluster of 10 to 40 pea-shaped flowers blooming from late spring through summer (May–August). Each flower is subtended by a calyx of five sepals fused at the base into a tubular cup about 5 to 8 mm long, with five pointed lobes that are lanceolate to ovate and often covered with fine hairs. Flowers are about 10 to 15 mm long. The corolla’s standard petal is broadly ovate and measures approximately 9 to 14 mm long and 7 to 10 mm wide; the wing petals are about 8 to 12 mm long and 3 to 5 mm wide; the keel, formed by two fused petals, is about 8 to 13 mm long and 3 to 5 mm wide. Flowers are typically purple to violet, sometimes pink or white. Flowers have ten stamens, nine of which are fused, and a superior ovary. The fruit is a spiral coiled pod about 2 to 4 cm long containing several seeds, maturing from late summer to early fall. Alfalfa is native to southwestern Asia but widely cultivated and naturalized in North America, including South Dakota. Primarily used as a forage crop, it is occasionally found naturalized along roadsides and disturbed sites.

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  Fabaceae: Melilotus albus

  R. Neil Reese

  Melilotus albus is a biennial or occasionally annual, herbaceous forb featuring a robust, deep taproot system. Plants typically reach a height of 50 to 200 cm at maturity, supported by upright, freely branched, glabrous to sparsely short-strigose, and often hollow stems. The leaves have an alternate insertion pattern and are palmately trifoliate, possessing a light to medium green color. Leaflets are generally oblong-lanceolate to obovate, measuring 1 to 3 cm long and 0.5 to 1.5 cm wide, with finely serrated margins along the upper half or more of their length, and smooth, glabrous upper and lower surfaces. A distinct petiole is present, ranging from 1 to 5 cm long, flanked at its base by a pair of linear-subulate, persistent stipules about 5 to 10 mm in length. Flowering occurs primarily from June through September, with individual white flowers tightly arranged along many narrow, elongated, spike-like racemes measuring 5 to 15 cm in length that emerge from the upper leaf axils. Each flower contains a small, persistent green calyx composed of five fused sepals forming a tube roughly 1.5 to 2 mm long with five equal, lanceolate lobes. The corolla features five free, white petals arranged in a classic pea-like structure measuring 3 to 5 mm long: an erect banner, two lateral wings, and two fused bottom petals forming a central keel, with the wings approximately equal to the keel in length. Tucked inside the corolla are 10 stamens containing small, yellow anthers; nine of the stamens are fused together by their filaments while one remains free (diadelphous arrangement). The single pistil consists of a superior, glabrous ovary about 2 mm long containing 1 to 2 ovules, ending in a slender, curved style and a minute, capitate stigma. The fruit develops into a small, ovoid, wrinkled, dark gray to brown legume measuring 3 to 4 mm long that remains mostly indehiscent and reaches full maturity from August through October. White sweetclover is not native to South Dakota; it was introduced from its native range across Europe and temperate Asia and can now be found extensively throughout all counties of South Dakota, thriving in disturbed soils, roadsides, agricultural fields, prairies, and riparian gravel bars.

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  Fabaceae: Melilotus officinalis

  R. Neil Reese

  Melilotus officinalis is a biennial or short-lived perennial herbaceous plant growing 30 to 150 cm tall. It has a deep taproot and a fibrous root system capable of fixing nitrogen. The stems are erect, slender, and often branched, with a smooth to sparsely hairy surface. Leaves are alternate and trifoliate, with three oval to obovate leaflets measuring about 1.5 to 4 cm long and 1 to 2 cm wide; leaflets have finely serrated margins and a smooth to slightly hairy surface. The leaflets are petiolulate with short stalks about 2 to 5 mm long, and stipules are small and lanceolate at the base of the leaf stalks. The inflorescence is a long, slender raceme of small, fragrant, bright yellow pea-shaped flowers blooming from late spring to early fall (May–September). Each flower is subtended by a calyx of five sepals fused at the base into a tubular cup about 3 to 6 mm long, with five pointed lobes that are lanceolate and often hairy. Flowers measure about 6 to 9 mm long. The corolla’s standard petal is broadly ovate, approximately 6 to 8 mm long and 4 to 6 mm wide; the wing petals are about 5 to 7 mm long and 2 to 3 mm wide; the keel, formed by two fused petals, is about 5 to 8 mm long and 2 to 3 mm wide. Flowers have ten stamens, nine of which are fused, and a superior ovary. The fruit is a small pod about 4 to 8 mm long containing one to two seeds. Yellow sweet clover is native to Eurasia but widely naturalized and sometimes invasive in North America, including South Dakota, commonly found in roadsides, fields, and disturbed habitats statewide.

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  Fabaceae: Mimosa nuttallii

  R. Neil Reese

  Mimosa nuttallii is a sprawling perennial herb with stems that grow up to 1 m long, covered with small prickles, 0.5-2 mm long. The alternate leaves are bipinnate leaf blades are divided into four to nine pairs (pinnae), and each of these have 8–15 pairs of leaflets, 3-9 mm long with a prominent midrib visible on the upper pairs and stipules 4-6 mm long. The leaves exhibit nyctinastic movement, folding up quickly when touched. The inflorescence consists of axillary, many-flowered heads, with peduncles 3-9 cm long. The pink to lavender flowers are sessile, with a minute calyx. The 5 united petals form a narrow tube about 4 mm long and lobes of about 1 mm, with 8-12 stamens inside. The fruit is a legume, 3-12 cm long and covered with prickles and explodes upon drying expelling the seeds. Nuttall’s sensitive briar blooms from April into September on prairies, in ravines and in open woodlands in central South Dakota.

  Synonym: Schrankia nutallii

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  Fabaceae: Oxytropis campestris

  R. Neil Reese

  Oxytropis campestris is a perennial, acaulescent (stemless) herbaceous forb anchored by a robust, deep, woody taproot system and a branched caudex. The plant grows from 5 to 30 cm tall. A true aerial stem is absent; instead, the leaves and flowering scapes emerge directly in dense, tufted basal rosettes from the crown. Leaf insertion is strictly basal. The leaves are odd-pinnately compound, stretching 3 to 20 cm in length. They comprise 11 to 35 leaflets that are grayish green to bright green. Each leaflet is lanceolate, oblong, or elliptic, measuring 5 to 25 mm long and 2 to 6 mm wide. Both upper and lower surfaces are covered in soft, appressed, silky-silvery hairs. The petioles are well-developed, measuring 2 to 8 cm long, and are flanked at the base by prominent, thin, papery stipules that are adnate to the petiole base and covered in fine hairs. Flowering occurs from May to July. The inflorescence is a dense, showy, spicate raceme or sub-capitate head elevated on an erect, leafless, hairy scape measuring 5 to 25 cm long, supporting 8 to 30 clustered flowers. The calyx consists of 5 sepals fused into a tubular, campanulate calyx tube that is 5 to 9 mm long and 2 to 3 mm wide. It terminates in 5 short, narrow teeth, colored light green to pale yellow, and characteristically covered in a mixture of white and conspicuous black hairs. The corolla is bilaterally symmetrical (papilionaceous) and composed of 5 free petals that are creamy-white, pale yellow, or occasionally tinged with purple. The broad upper standard petal stands 12 to 18 mm long; the two side wing petals are oblong, while the bottom two petals are fused into a narrow keel petal that is explicitly distinguished by a sharp, abrupt point at the apex (a diagnostic feature separating Oxytropis from Astragalus). The androecium contains 10 stamens configured in a diadelphous arrangement (9 filaments fused into a tube surrounding the pistil and 1 filament completely free), supporting small, bright yellow anthers. The gynoecium consists of a single pistil featuring a superior, oblong, unilocular ovary, a slender, inwardly curved style, and a minute, capitate stigma. The fruit is a dry, erect to spreading, oblong-ovoid legume capsule measuring 10 to 20 mm long. It features a short, hooked beak, is covered in short hairs, and changes from light green to a brittle, dark brownish-black color as it reaches maturity between July and September. Field locoweed is native to South Dakota. Within the state, its distribution is restricted to the western counties, primarily tracking the limestone plateaus, high ridges, and gravelly slopes of the Black Hills. It thrives in exposed, well-drained, and nutrient-poor habitats such as alpine meadows, native shortgrass prairies, rocky outcrops, and gravelly river bluffs.

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  Fabaceae : Oxytropis lambertii

  R. Neil Reese

  Oxytropis lambertii is an acaulescent perennial herb growing from a branching caudex, forming clumps of leaves that appear silvery due to a covering of short stiff and ax-shaped hairs. The leaves are up to 15 cm long with 7 to 19 linear-lanceolate leaflets, 5-40 mm long and 1-6 mm wide, with membranous, hairy stipules 7–24 mm long and having sharply pointed tips. Inflorescences develop on multiple, silvery-haired flowering stems (scapes), 10–30 cm long including the peduncle, each with 6 to 25 flowers per raceme. The calyx has a dense white covering of hairs, the sepals forming a tube that is 6-7 mm long with teeth 1.5-3 mm long. The papilionaceous flowers have red to blue to purple petals, the banner 15–25 mm long, the wings 12-20 mm long and the keel 13-19 mm long. The fruit is an silvery-haired, erect, sessile leathery or woody legume, 1–2 cm long, including the long beak. Purple locoweed blooms from May into August on prairies, plains, river bluffs and hillsides in much of South Dakota.

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  Fabaceae : Oxytropis sericea

  R. Neil Reese

  Oxytropis sericea is an acaulescent perennial herb growing from a much-branched caudex, forming mounds of silky-haired leaves. The leaves are 4-30 cm long with 11 to 25 lanceolate to narrowly ovate leaflets, 5–40 mm long and 2-10 mm wide. The petioles are 1-15 cm long with membranous, hairy stipules, 8–22 mm long. Inflorescences are terminal racemes of 6 to 30 flowers atop of erect to ascending scapes (flowering stems), 5–30 cm long, including the peduncle. The calyx is covered in white and/or black hairs, and forms a tubular-campanulate tube, 8-12 mm long with unequal teeth 2-5 mm long. The papilionaceous corolla is white to yellowish white; the banner 16–25 mm long and deeply lobed, the wings 15-20 mm long, and the keel is 12-17 mm long with a small appendage at the distal end. The fruit are sessile, erect, oblong legumes, 15–25 mm long, with a short beak and having a few short stiff hairs to a silky covering of hair. White locoweed blooms from April into June in rocky prairies, hillsides, open woods and valleys in southwestern South Dakota.

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  Fabaceae : Pediomelum argophyllum

  R. Neil Reese

  Pediomelum argophyllum is a perennial herb with multiple, erect to ascending, widely branching stems, 20-80 cm in height, growing from a subterranean caudex that forms colonies. The stems are usually covered in silvery hairs. The alternate leaves are palmately compound with 3 to 5 leaflets with 1-5 cm long petioles. The leaflets are 1–4 cm long, with entire margins, and covered with dense, shiny hairs. The inflorescence consists of axillary spikes, 2–9 cm long including the peduncle, with 1 to 5 leafy bracts and 2-5 well separated whorls of 3-6 flowers each. The densely hairy calyx forma a campanulate tube with 2 lips, 2–3 mm long with 4 upper teeth, 2.5-3 mm long and a lower tooth 7-10 mm in length. The purple, papilionaceous corolla has a banner 5-7 mm long with a short spur, the wings are 4-6 mm long and the keel 4-5 mm long. The fruit is a hairy, 1-seeded legume, 7-9 mm long with a short beak, and mostly enclosed by the calyx. Silverleaf scurf-pea blooms from July into September on prairies, hillsides, open woodlands, sand dunes and in stream valleys throughout South Dakota.

  Synonym: Psoralea argophylla,

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  Fabaceae : Pediomelum esculentum

  R. Neil Reese

  Pediomelum esculentum is a perennial herb with a tuberous-thickened root, 4-10 cm below ground and with 1-3 caudices extending to the soil surface, producing 1-3 simple or rarely branched stems, 8 to 30 cm in height and covered with a dense pubescence. The alternate leaves are palmately compound with 5 leaflets attached to a petiole that is 5-10 cm long, with stipules 1-2 cm long. The leaflets are elliptic to ovate, 2–4 cm long, 7-18 mm wide, narrowing at the base, rounded, blunt or pointed at the tip. The upper surface is usually nearly smooth, and the lower surfaces are covered in flattened hairs. The inflorescences are axillary spike-like racemes, 5–12 cm long including the peduncle, and the spikes 2-2.5 cm wide. The calyx tube is 5-6.5 mm long, with 5 teeth, the upper 4 are 5-7.5 mm long, the middle 2 partially united, and the lower-most tooth 6-8 mm long. The papilionaceous corolla is blue with clawed (constricted at the base) petals, the petals beyond the claws measure: banner 9-13 mm, wings 9-13 mm and the keel 4-5 mm long. The fruit is an ovoid, single-seeded legume, 5-7 mm long, enclosed in the calyx. Prairie turnips bloom from May into July in prairies, open woodlands, on hillsides and in stream valleys throughout South Dakota.

  Synonym: Psoralea esculenta

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  Fabaceae: Securigera varia

  R. Neil Reese

  Securigera varia is a perennial herbaceous vine or groundcover growing from a fibrous root system. The stems are slender, sprawling to trailing, smooth or slightly hairy, and can reach up to 1 to 2 meters long, often forming dense mats. The leaves are alternate and pinnately compound with 15 to 25 leaflets. Each leaflet is oblong to lanceolate, measuring 1 to 3 cm long and 0.5 to 1.5 cm wide, often with a small tooth-like point at the tip. The upper leaf surface is dark green and glabrous (smooth), while the lower surface is lighter green and may have fine hairs. Leaf margins are entire or slightly serrated. Petioles are short, typically 1 to 3 cm long, supporting the leaflets in a feather-like arrangement. Plants bloom from June through September. The inflorescence is a terminal umbel with 15 to 30 pink to lavender flowers, each about 15 to 20 mm in diameter. Each flower has five free, small green sepals that are ovate and about 2 to 3 mm long, and five free petals forming the typical papilionaceous (butterfly-like) shape of legumes: a large banner petal (10–15 mm), two wing petals (8–12 mm), and two keel petals (7–10 mm) fused at the base. There are ten stamens per flower, nine filaments fused into a tube and one free (diadelphous), and yellow anthers about 1 to 2 mm long. The pistil is single with one carpel forming a simple ovary about 5 to 7 mm long, a style about 6 to 8 mm long, and a small stigma. The fruit is a slender, cylindrical legume pod about 3 to 6 cm long that ripens from August to October and contains several seeds. . Crownvetch is native to Europe and Asia but has become naturalized in South Dakota, commonly found in disturbed sites, open fields, roadsides, and is used as a groundcover in erosion control plantings, primarily in the eastern parts of the state.

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  Fabaceae: Strophostyles leiosperma

  R. Neil Reese

  Strophostyles leiosperma is an annual or short-lived perennial, herbaceous vine with a slender, twining or trailing form. It grows from a taproot. Vines typically reach 30 to 120 cm in length and may climb or sprawl over adjacent vegetation. Stems are thin, green to purplish, and covered with fine, appressed hairs. Leaves are alternate and trifoliate. Leaflets are oblong to ovate, 2–6 cm long and 1–3 cm wide, with entire to slightly lobed margins and a pointed tip. Leaf color is medium to dark green above and paler below, sometimes with sparse appressed hairs on both surfaces. Petioles are present and usually 1–5 cm long. Stipules are present at the base of the petiole, small and linear, but easily overlooked. Flowering occurs from June to September. The inflorescence is a short, axillary raceme bearing 1–6 papilionaceous (pea-like) flowers. Each flower is about 1–2 cm long. The calyx consists of five green sepals, 3–7 mm long, fused at the base with short, broad lobes and fine hairs. The corolla has five petals, with the standard (banner) petal being pink to pale purple (sometimes white), broad and slightly notched, and about 12–20 mm long; the wings and keel are smaller, pale pink to white. There are ten stamens, nine fused and one free, with white filaments and yellow anthers, typical of the pea family. The pistil is single, about 1 cm long, with a slender style and a small, capitate stigma. Fruit is a slender, straight or slightly curved pod (legume), 3–6 cm long and about 5 mm wide, green turning brown at maturity, usually from August to October. The pod splits open to reveal smooth, oval seeds (a distinguishing feature), tan to brown, about 3–4 mm long. Slick-seed fuzzybean is native to South Dakota, found mostly in the eastern and southeastern parts of the state in open woodlands, prairies, roadsides, and disturbed sites, particularly in sandy soils.

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  Fabaceae : Thermopsis rhombifolia

  R. Neil Reese

  Thermopsis rhombifolia is a perennial rhizomatous herb, with 1 to several ascending to erect stems, 15–60 cm tall, with or without a covering of short, stiff hairs. This species is often colony forming in open prairies. The alternate, palmately trifoliate leaves have leaflets that are ovate, 15–50 mm long and 10-20 mm wide, with a few to many appressed hairs. The inflorescence consists of subterminal racemes, 3–10 cm long. The calyx forms a hairy, bilabiate tube, 4-5 mm long, the upper lip having 2 united teeth, 3-4 mm long , and the lower lip with 3 teeth 2-3 mm long. The papilionaceous corolla has yellow petals, the banner often has purple spots and is 17-22 mm long, the wings are 15- 18 mm long, and the oblong keel is 14-16 mm long. The flowers have 10 separate stamens. The fruit is a legume, 3–8 cm long with 3 to 10 seeds, constricted between the ~5 mm long seeds. Goldenpea blooms from April into June on open prairies, hillsides and woodlands in western South Dakota.

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  Fabaceae : Vicia americana

  R. Neil Reese

  Vicia americana is a rhizomatous, perennial herb, the stems sprawling to climbing, 20-100 cm long and smooth to having a sparse covering of hairs . The alternate leaves are compound pinnate with 4 to 8 pairs of elliptical to linear leaflets 10-38 mm long , a pair of stipules ~8 mm long, and with a tendril at the end of the leaf. The inflorescences are racemes in the axils of the upper leaves. The peduncles are well developed with 3-10 flowers. The calyx forms a tube 3.5-5.5 mm long with unequal teeth, the upper short and broad the lower narrower and pointed, 1.2-4 mm long. The papilionaceous corolla is blue to purple, rarely white. The banner is 12-25 mm long and the wings and keel shorter. The fruit is a legume, 2.5-3.5 cm long with 2-14 seeds. American vetch blooms from May to July in a variety of dry, open to moist, shaded habitats; mixed grass prairie, sagebrush steppe, meadows, pine forest, and deciduous woodlands throughout South Dakota.

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  Fumariaceae : Dicentra cucullaria

  R. Neil Reese

  Dicentra cucullaria is perennial herb, which grows 6 cm to 30 cm in height, with the flower stems and basal leaves rising directly from a scaly rootstock. The erect to ascending basal leaves have long petioles (5-15 cm}, the compound pinnatifid blades are ovate to triangular, 10-26 cm long, divided 2-3 times into lacy segments 1-3 mm wide, with entire margins. The flowering stems (scapes) are 10-30 cm tall, terminating in a raceme of 3-15 flowers, subtended by whitish bracts. The flowers are shaped like pantaloons. The 2 membranaceous sepals are white, sometimes streaked with purple, 2-3.5 mm long and 1.5-2.5 mm wide. The 4 white petals are yellow tipped, the outer 2 petals are spurred 10-15 mm long, the inner pair, oblanceolate, 7-12 mm long and convergent coherent at the top. The fruit is a capsule, 10-15 mm long, 3-6 mm in diameter. Dutchman’s breeches bloom from March into May in moist woods in eastern South Dakota.