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  Asteraceae: Solidago simplex

  R. Neil Reese

  Solidago simplex is a perennial, herbaceous plant with a fibrous root system and short, slender rhizomes, forming loose tufts or small colonies. Mature plants typically reach 20–70 cm in height. Stems are erect, slender, often reddish at the base, and usually glabrous or with sparse, fine hairs; in some subspecies, the upper stem may be glandular-sticky. Leaves are alternate, simple, and mostly linear to narrowly lanceolate; basal leaves are the largest, 8–20 cm long and 0.5–2 cm wide, with a prominent midvein and entire or slightly toothed margins. Basal leaves taper to a short petiole (1–3 cm), while upper leaves are much smaller (2–8 cm long, 2–7 mm wide), progressively reduced and sessile toward the inflorescence. Leaf surfaces are green, with the upper surface smooth and the lower surface sometimes sparsely hairy or glandular. Stipules are absent. Flowering occurs from July to September, with the inflorescence forming a narrow, erect or one-sided raceme or panicle up to 15 cm long, with numerous small, bright yellow flower heads. Each involucre is narrowly bell-shaped, 2–3 mm long, with several overlapping, green to yellowish, lanceolate phyllaries, sometimes glandular. Each head contains 6–12 yellow ray florets (2–3 mm long, 0.5–1 mm wide) and 3–8 yellow disc florets. Stamens are five per disc floret, with yellow anthers about 1–1.5 mm long, forming a tube around the style. The pistil consists of a single compound ovary per floret, with a slender style about 2 mm long and a bifid stigma. The fruit is a small, ribbed cypsela (achene), 1–2 mm long, brown when mature in late summer to early fall, each topped with a single row of white to pale brown pappus bristles. Sticky goldenrod is native to South Dakota and is found in mountainous areas in the western part of the state, in prairies, roadsides, rocky outcrops, sand dunes, and dry, open habitats with well-drained soils in full sun.

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  Asteraceae: Sonchus arvensis

  R. Neil Reese

  Sonchus arvensis is a perennial, herbaceous plant with a deep, extensive creeping root system and stout rhizomes, often forming dense colonies. Mature plants typically reach 60–150 cm in height. The stems are erect, hollow, branched above, and glabrous or sparsely hairy, often exuding a milky sap when cut. Leaves are alternate, simple, oblong to lanceolate, 10–35 cm long and 2–8 cm wide, deeply pinnately lobed with prickly, undulate margins; basal leaves are larger and taper to a winged petiole, while upper leaves are smaller, more clasping, and often auriculate (with ear-like lobes at the base). Both surfaces are green, with the upper surface smooth and the lower surface sometimes sparsely hairy along the veins. Petioles are present on basal leaves; upper leaves are sessile and clasp the stem. Stipules are absent. Flowering occurs from July to September, with the inflorescence forming a loose, branched corymb or panicle up to 20 cm across, composed of several to many large, dandelion-like heads. Each head is 3–5 cm across, with an involucre 15–20 mm long, composed of several rows of overlapping, lanceolate green phyllaries that are often glandular and sticky. The heads contain only yellow ray florets (ligulate), 15–30 mm long and 2–4 mm wide; there are no disc florets. Five stamens are fused to the corolla tube, with yellow anthers about 3–4 mm long. The pistil consists of a single compound ovary per floret, with a slender style 8–10 mm long and a two-branched stigma, both yellow. The fruit is a compressed, ribbed, brown achene, 3–4 mm long, topped with a white, silky pappus up to 12 mm long for wind dispersal; fruits mature from August to October. Field sow-thistle is introduced in South Dakota, native to Europe and Asia, and is now widely established in disturbed habitats such as croplands, roadsides, ditches, pastures, and waste areas, especially in moist, fertile soils.

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  Asteraceae : Symphyotrichum ciliolatum

  R. Neil Reese

  Symphyotrichum ciliolatum is a perennial herb growing from a rhizome or occasionally from a short caudex and reaching 30-100 cm in height. The stems are mostly smoot toward the base and have short hairs towards the upper regions. The lower leaves are alternat, ovate to lanceolate with some of them contracted near the base forming a distinct petiole. The blade is toothed, 8-15 cm long and 2-6 cm wide and somewhat hairy beneath. The inflorescence is a panicle of a few to many heads, generally < 50 but occasionally more than 100. Each head has an involucre that is 5-7 mm tall with overlapping slender bracts that are yellowish white at the base. There are 15-25 ray flowers with blue-purple ligules 7-12 mm long and about 25 reddish purple disk flowers that slightly exceed the pappus. The fruit are flattened achenes, yellowish colored with minutely plumose bristles 3-6 mm long. Lindley’s aster blooms from July through October on rocky moist soils especially in open wooded areas.

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  Asteraceae: Symphyotrichum ericoides

  R. Neil Reese

  Symphyotrichum ericoides is a perennial, herbaceous plant with a fibrous root system and slender, creeping rhizomes, forming dense, spreading colonies. Mature plants typically reach 30–80 cm in height. Stems are erect, slender, often much branched, and covered with short, fine hairs. Leaves are alternate, simple, narrow, and linear to lanceolate, 1–4 cm long and 1–3 mm wide, with entire margins and a pointed tip. Leaf surfaces are medium green and slightly rough or hairy, especially on the lower surface, and the leaf blades are sessile. Flowering occurs from August to October, with inflorescences forming dense, branched, leafy panicles up to 30 cm long and wide, with many small daisy-like flower heads. Each head is surrounded by a cylindric involucre, 3–5 mm long, with several rows of overlapping, green, lanceolate phyllaries with translucent margins. Each head contains 12–20 narrow, white ray florets, each 3–5 mm long and 0.5–1 mm wide, and 5–10 yellow disc florets. Stamens are five per disc floret, with yellow anthers about 1 mm long, forming a tube around the style. The pistil consists of a single compound ovary per floret, with a slender style about 2 mm long and a bifid (two-parted) stigma. The fruit is a small, dry, ribbed cypsela (achene), 2–2.5 mm long, grayish brown, maturing in fall; each is topped with a white, hair-like pappus 3–5 mm long for wind dispersal. Heath aster is native to South Dakota and occurs throughout the state in prairies, open woodlands, roadsides, and disturbed areas, especially in dry, sandy, or gravelly soils in full sun.

  Synonyms: Aster ericoides, Aster falcatus

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  Asteraceae: Symphyotrichum laeve

  R. Neil Reese

  Symphyotrichum laeve is a perennial, herbaceous plant with a fibrous root system and short, creeping rhizomes, sometimes forming loose clumps or small colonies. Mature plants typically reach 40–100 cm in height. Stems are erect, slender, and mostly hairless (glabrous), often with a bluish or glaucous waxy coating. Leaves are alternate, simple, lanceolate to ovate, 4–15 cm long and 1–4 cm wide, with smooth (entire) margins and a pointed tip. Basal and lower stem leaves are larger and may have short petioles, while upper leaves are smaller, clasping the stem with an auriculate (ear-like lobe) base. Leaf surfaces are blue-green, smooth, and glabrous above and below, giving the foliage a characteristic sheen. Flowering occurs from August to October, with inflorescences forming open, branched, leafy panicles up to 30 cm long, each with numerous showy, daisy-like flower heads, subtended by a cylindric involucre, 5–7 mm long, composed of several rows of overlapping, green to purplish, lanceolate phyllaries with translucent margins. Each head contains 15–25 pale blue to lavender ray florets (petals), each 8–15 mm long and 2–3 mm wide, and 15–30 yellow disc florets. Stamens are five per disc floret, with yellow anthers about 1.5 mm long, forming a tube around the style. The pistil consists of a single compound ovary per floret, with a slender style about 3 mm long and a bifid (two-parted) stigma. The fruit is a small, dry, ribbed cypsela (achene), 2–3 mm long, brown when mature in fall; each is topped with a white or pale brown, hair-like pappus 4–6 mm long. Smooth blue aster is native to South Dakota and found throughout the state in prairies, open woodlands, roadsides, and rocky hillsides, typically in well-drained, calcareous, or sandy soils in full sun.

  Synonym: Aster laevis

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  Asteraceae: Symphyotrichum lanceolatum

  R. Neil Reese

  Symphyotrichum lanceolatum is a perennial, herbaceous plant with a fibrous root system and long, creeping rhizomes, frequently forming dense colonies. Mature plants typically reach 60–150 cm in height. Stems are erect, slender, often branching in the upper half, and smooth or slightly roughened, sometimes with sparse, fine hairs. Leaves are alternate, simple, and lanceolate to narrowly elliptic, 5–20 cm long and 0.5–3 cm wide, with entire or finely toothed margins and pointed tips. Basal leaves may have short petioles and are often withered by flowering time; stem leaves are sessile, often clasping the stem with a heart-shaped or auriculate base. Leaf surfaces are medium to dark green, smooth or slightly rough above, and glabrous or slightly hairy below. Stipules are absent. Flowering occurs from August to October, with inflorescences forming large, spreading, and branched panicles up to 30 cm long, each with many daisy-like flower heads. Each involucre is cylindric, 4–6 mm long, with 3-6 rows of overlapping, green, lanceolate phyllaries with translucent margins, the outer layer shorter than the inner. Each head contains 12–25 white (occasionally pale blue or pink) ray florets (petals), each 5–9 mm long and about 1 mm wide, and 8–20 yellow disc florets. Stamens are five per disc floret, with yellow anthers about 1 mm long, forming a tube around the style. The pistil consists of a single compound ovary per floret, with a slender style about 2 mm long and a bifid (two-parted) stigma. The fruit is a small, dry, ribbed cypsela (achene), 2–2.5 mm long, brown when mature in fall (October to November); each is topped with a white, hair-like pappus 3–5 mm long for wind dispersal. White panicle aster is native to South Dakota and is found statewide in moist prairies, meadows, stream banks, ditches, and open woods, typically in moist to moderately moist, well-drained soils under full sun to partial shade.

  Synonym: Aster lanceolatus

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  Asteraceae: Symphyotrichum novae-angliae

  R. Neil Reese

  Symphyotrichum novae-angliae is a perennial, herbaceous plant with a fibrous root system and short, stout rhizomes, forming upright clumps rather than spreading colonies. Mature plants typically reach 90–180 cm in height. Stems are erect, stout, and densely covered with short, stiff hairs, often with a reddish tint. Leaves are alternate, simple, lanceolate to oblong, 5–15 cm long and 1–3 cm wide, with entire to slightly toothed margins and pointed tips. Basal leaves have short petioles and may be withered by flowering time; stem leaves are sessile and clasp the stem with an auriculate (ear-like) base. Leaf surfaces are medium to dark green, rough and hairy above and below, giving the foliage a coarse texture. Flowering occurs from August to October, with inflorescences forming large, showy, branched panicles up to 30 cm wide, each with numerous daisy-like flower heads. Each head is subtended by a cylindric involucre, 7–10 mm long, with several rows of overlapping, green to purplish, lanceolate phyllaries with translucent margins. Each head contains 30–60 violet to purple (rarely pink or white) ray florets (petals), each 10–20 mm long and 1–2 mm wide. The disc florets are numerous (30–50 per head), tubular, 5–7 mm long, yellow at anthesis (turning reddish-brown with age), with five small lobes at the tip. Stamens are five per disc floret, with yellow anthers about 1.5 mm long, forming a tube around the style. The pistil consists of a single compound ovary per floret, with a slender style about 3 mm long and a bifid stigma. The fruit is a small, dry, ribbed cypsela (achene), 2–3 mm long, brown when mature in autumn (September through November); each is topped with a tawny to white, hair-like pappus 4–6 mm long. New England aster is native to South Dakota and is found throughout the state in moist prairies, meadows, stream banks, roadside ditches, and open woods, typically in moderately moist, well-drained soils under full sun to partial shade.

  Synonym: Aster novae-angliae

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  Asteraceae: Symphyotrichum pilosum

  R. Neil Reese

  Symphyotrichum pilosum is a perennial, herbaceous plant with a fibrous root system and slender, creeping rhizomes, forming loose colonies or clumps. Mature plants typically reach 50–120 cm in height. Stems are erect, much-branched above, slender, and densely covered with long, spreading white hairs (pilosity) that give the plant a rough texture. Leaves are alternate, simple, and lanceolate to narrowly oblanceolate, ranging from 3–10 cm long and 0.5–2 cm wide, with entire or slightly toothed margins and a pointed tip; basal leaves are larger with winged petioles up to 2 cm long, but most leaves are sessile and become smaller and narrower toward the top. Leaf surfaces are medium to dark green above, lighter below, and both surfaces are hairy, especially along the veins and margins. Flowering occurs from August to October, with inflorescences forming large, open, branched panicles up to 30 cm wide, each with numerous small daisy-like flower heads. The subtending involucres are cylindric, 3–5 mm long, with several rows of overlapping, green, lanceolate phyllaries with translucent margins. Each head contains 15–35 white, occasionally pinkish, ray florets (petals), each 4–8 mm long and 1 mm wide. The disc florets are numerous (10–25 per head), tubular, 4–5 mm long, yellow at first and turning reddish-brown as they age, with five small lobes at the apex. Each disc floret has five stamens with yellow anthers about 1 mm long, forming a tube around the style, and a single compound ovary with a slender style about 2 mm long and a bifid stigma. The fruit is a small, dry, ribbed cypsela (achene), 1.5–2 mm long, gray-brown when mature, each topped with a white, hair-like pappus 3–5 mm long for wind dispersal; fruits mature from September to November. Hairy aster is native to South Dakota and is found throughout the state in prairies, open woodlands, roadsides, old fields, and disturbed areas, especially in dry, sandy, or gravelly soils under full sun.

  Synonym: Aster pilosus

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  Asteraceae: Symphyotrichum sericeum

  R. Neil Reese

  Symphyotrichum sericeum is a perennial, herbaceous plant with a fibrous root system and short, thick rhizomes or a branched caudex, forming small, upright clumps. Mature plants typically reach 30–60 cm in height. Stems are erect, unbranched or sparsely branched, and densely covered with fine, silky, silvery hairs that give the plant a distinctive sheen. Leaves are alternate, simple, and narrowly lanceolate to linear, 4–12 cm long and 3–10 mm wide, with entire margins and pointed tips; both surfaces are densely covered with silky, silvery hairs, giving a soft texture and pale blue-green appearance. Basal leaves generally have short petioles and are often withered by flowering time; stem leaves are sessile and become smaller toward the top. Flowering occurs from August to October, with inflorescences forming small, open clusters (panicles or racemes) of showy, daisy-like flower heads, each 2–4 cm across. Each involucre is cylindric, 7–10 mm long, with several overlapping rows of green to purplish lanceolate phyllaries with translucent margins. Each head contains 15–30 bright lavender to purple ray florets, each 10–18 mm long and about 2 mm wide. The disc florets are numerous (15–30 per head), tubular, 5–7 mm long, yellow at anthesis, turning purplish with age, with five small lobes at the tip. Each disc floret has five stamens with yellow anthers about 1.5 mm long, forming a tube around the style, and a single compound ovary with a slender style about 3 mm long and a bifid stigma. The fruit is a small, dry, ribbed cypsela (achene), 2–2.5 mm long, brown when mature, each topped with a pale brown to white, hair-like pappus 4–6 mm long; fruits mature from September to November. Silky aster is native to South Dakota and occurs primarily in dry prairies, open hillsides, rocky outcrops, and sandy or gravelly soils under full sun, often in association with other drought-tolerant prairie species.

  Synonym: Aster sericeus

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  Asteraceae : Tanacetum vulgare

  R. Neil Reese

  Tanacetum vulgare is a perennial herb with erect, usually smooth stems arising from a branched rhizome, singly or in clusters growing 50–150 cm tall and branching near the top. The plant is strongly scented and has numerous, alternate, twice pinnately divided, fern-like green leaves. The inflorescence consist of numerous (up to 200) heads in a corymbiform cyme. The heads are disk shaped, hemispheric at maturity, 5-10 mm in diameter and surrounded by an involucre of overlapping bracts. The outer yellow disc flowers are tubular and 3-toothed and the inner corollas are 5-toothed. The achenes are 5-sided with a short crown-like pappus. Tansy blooms in July and August in waste places stream banks and flood plains in the eastern and western edges of South Dakota.

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  Asteraceae : Townsendia exscapa

  R. Neil Reese

  Townsendia escapa is a perennial dwarf growing from a branched caudex, forming small mats. The stems are about 1 cm in height and inconspicuous. The leaves are simple, entire, linear-lanceolate, 1–5 cm long, 2-6 mm wide, with short stiff hairs and appressed hairs on their surfaces. The inflorescence is 1 or more heads, sessile laying among the leaves. The involucre is broadly campanulate, 1-2 cm tall with 4-7 series of bracts. There are 20-40 ray flowers, the ligules 10–22 mm long, white to pink. The yellow disk corollas are 8–10 mm long . The achenes are flattened, 3.5-6 mm long, pubescent and have a long bristly pappus. Townsend’s daisy blooms in early spring (April-May) on open dry plains in southwestern South Dakota.

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  Asteraceae: Tripleurospermum perforatum

  R. Neil Reese

  Tripleurospermum perforatum is a perennial, herbaceous plant with a fibrous root system and creeping rhizomes, often forming dense mats. Mature plants typically reach 20–80 cm in height. Stems are erect, branched, slender, and green to reddish, often sparsely hairy or glabrous. Leaves are alternate, pinnately divided, and fern-like, 5–15 cm long, with numerous small, narrow, linear to lanceolate lobes; leaves are bright green, with translucent oil glands visible as tiny dots when held to light (hence “perforatum”). Petioles are short or absent. Flowering occurs from June to September, with inflorescences forming solitary or few-flowered terminal heads resembling small daisies, 2–3 cm in diameter. Each flower head has a prominent involucre composed of several overlapping, green bracts (phyllaries) that are lanceolate to ovate, 8–12 mm long and 3–5 mm wide, with membranous margins. The flower head contains numerous white ray florets (20–30), each 6–12 mm long and 1–2 mm wide, and a dense central disc of yellow disc florets (30–50), tubular and 3–5 mm long with five small lobes at the apex. Stamens number five per disc floret, with yellow anthers about 1 mm long forming a tube around the style. The pistil is single with a slender style and bifid stigma. The fruit is a small, dry, ribbed achene (cypsela), 2–3 mm long, with three distinctive ribs and two resinous glands, maturing from August to October. Scentless chamomile is introduced in South Dakota, native to Eurasia, and found in disturbed sites such as fields, roadsides, pastures, and waste areas, thriving in well-drained, sandy to loamy soils under full sun.

  Synonym: Matricaria perforata

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  Asteraceae : Vernonia fasciculata

  R. Neil Reese

  Vernonia fasciculata is a perennial herb from a fibrous rooted base, 60-120 cm tall and unbranched or branched only near the top. The stem is round, hairless, and greenish to reddish purple. The alternate, simple lanceolate leaves are sessile or have very short petioles, 4-15 cm long and 5-45 mm wide. Their margins are toothed, the leaf surfaces are hairless, the lower leaf surface having a prominent central vein, and often small black dots. The inflorescence is a flat-topped cluster of heads with each head has an involucre of overlapping bracts, the inner ones longer than the outer bracts, their pedicels usually slightly pubescent. There are 10-30 magenta disk flowers, the corollas 9-11 mm long, with 5 spreading lobes and a prominent divided style. The achenes are ~3 mm long with a brown to purplish pappus that is about twice as long. Ironweed blooms from July through October in damp prairies and along streambanks throughout South Dakota.

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  Balsaminaceae : Impatiens capensis

  R. Neil Reese

  Impatiens capensis an annual herb with simple (occasionally branching), round, hollow stems that are smooth, succulent, pale green to pale reddish green, and somewhat translucent, growing 50-150 cm tall. The alternate, petiolate leaves are ovate to elliptic-ovate, 3-10 cm long and 2-7 cm wide, thin-textured, with rounded teeth. The leaf’s upper surface is green and the lower pale and waxy. The inflorescence consists of small clusters of 1-3 orange flowers, held horizontally on drooping pedicels from the axils of leaves. Each orange to red flower is 2-3 cm long, irregularly conical with upper and lower lips and a 6-9 mm spur that is bent back and parallel to the body. The petals usually have crimson to variously colored spots. The fruit is a 5-celled capsule and the mottled green to brown seeds are 4-5 mm long. When touched, the capsules explode and forcefully eject the seeds. Spotted touch-me-not blooms from May through October in moist woodlands, along streambanks and in marshes in eastern and southwestern South Dakota.

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  Boraginaceae: Buglossoides arvensis

  R. Neil Reese

  Buglossoides arvensis is an annual or biennial herb with an erect growth form, typically reaching 30–80 cm in height. It has a taproot system and reproduces solely by seed. The stems are branched and densely covered with rough, short hairs, giving a bristly texture. Leaves are alternate, simple, lanceolate to ovate-lanceolate, 3–10 cm long, with entire or slightly toothed margins, and rough, hairy surfaces. Basal leaves are larger and ovate, while cauline leaves are smaller and narrower. Flowering occurs from late spring to early fall. The inflorescence is a scorpioid cyme—a coiled cluster of small, tubular flowers 8–12 mm long, with five fused petals forming a trumpet shape. Flowers are pale blue to violet with darker markings and a hairy throat. Each flower has five sepals, five stamens attached to the corolla, and a single pistil. The fruit is composed of four small nutlets (seeds), maturing in late summer. Native to temperate Europe and Asia, Corn Gromwell has been introduced and naturalized in parts of North America, including South Dakota, where it grows in disturbed fields, roadsides, and agricultural lands, mostly in eastern and central regions.

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  Boraginaceae: Cryptantha celosioides

  R Neil Reese

  Cryptantha celosioides is a biennial or short-lived perennial with 1 to several erect, simple to branched stems, 6–35 cm tall, growing from a caudex and covered with bristly hairs. There are both basal and alternate cauline leaves that are covered with grayish bristly hairs. The basal leaves are petiolate, the blades 1–6 cm long, spatulate to oblanceolate, the tips rounded to obtuse. The cauline leaves are narrower with pointed tips and usually less densely covered with hairs. The inflorescence is a collection of terminal cymes at the branch tips, condensed when young and uncoiling with age. The hairy calyx is 7–10 mm long in fruit and the white corolla is 3–6 mm long, 6–11 mm across the limb, often with a yellow coloring in the throat (fornices). The fruit are 4 ovate nutlets, 3–4 mm long. Buttecandle blooms from May into July in dry pastures and canyons in western South Dakota.

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  Boraginaceae : Lithospermum canescens

  R. Neil Reese

  Lithospermum canescens in a perennial herb from vertical taproot with erect stems, 12-35 cm tall, simple or branched above. The leaves are cauline, often ascending, lanceolate to elliptic, the tips obtuse, 20-55 mm long and 4-11 mm wide, covered with soft grayish white hairs. The inflorescence consists of cymes at the branch tips. The flowers have green sepals 4-17 mm long and a yellow to yellow-orange funnel-shaped corolla 7-18 mm long, 7–14 mm wide at the top, the lobes with entire edges. The fruit are smooth and shiny nutlets 3–4 mm long. Hoary puccoon blooms from April to June on dry prairies and open woods in eastern and southern South Dakota.

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  Boraginaceae : Lithospermum incisum

  R. Neil Reese

  Lithospermum incisum in a perennial herb from a woody branched caudex, with stems prostrate to erect, 5–25 cm long and branched above, with many stiff straight and appressed hairs. The leaves are predominantly cauline, linear to linear-lanceolate with pointed tips, 13-45 mm long and 4-20 mm wide. The inflorescence may have flowers in the upper leaf axils or cymes at the branch tips. The flowers have green sepals 6–9 mm long and a yellow to yellow-orange funnel-shaped corolla 2–4 cm long, 7–12 mm wide at the top, usually with fringed lobes and the style slightly exerted. The fruit are nutlets 3–4 mm long. Fringed puccoon blooms from April to June on dry prairies, open woods and disturbed areas over much of South Dakota.

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  Boraginaceae: Onosmodium bejariense

  R. Neil Reese

  Onosmodium bejariense is a perennial herbaceous plant with a woody base, growing 30 to 90 cm tall with erect, branched stems densely covered in coarse, spreading hairs that give a rough texture. The alternate leaves are lanceolate to narrowly ovate, 5 to 15 cm long and 1 to 4 cm wide, with entire to slightly wavy margins, short petioles and a rough, hairy surface. Flowering occurs in mid-summer (May–July). The flowers are born in terminal and axillary cymes. Each flower has five sepals fused at the base, each sepal about 5–8 mm long, narrowly lanceolate and hairy forming a calyx tube about 6 to 10 mm long with pointed lobes. The corolla consists of five white petals fused into a tubular shape 10 to 15 mm long and 4 to 6 mm wide. with 5 hairy, green to yellow-tinged, triangular lobes at the tip that close the mouth of the tube. A long white style projects from the tube and remains long after the petals wilt away. The flower contains five stamens epipetalous (attached near the base of the corolla tube), with slender filaments and yellow anthers enclosed within the tube. The pistil has a superior ovary with a single style approximately 6 to 8 mm long, extending beyond the stamens. And terminating in a bifid stigma with rounded lobes about 1 to 2 mm wide. Fruits develop from August through September as four brown, smooth, slightly glossy nutlets, each about 3 to 5 mm long. Western false gromwell is native to South Dakota, typically found in sandy or rocky prairies, open woodlands, and well-drained upland sites across much of the state.

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  Boraginaceae: Phacelia hastata

  R. Neil Reese

  Phacelia hastata is a perennial herbaceous plant growing 15 to 60 cm tall from a fibrous root system with a woody base. The roots are slender and moderately deep, anchoring the plant in well-drained soils. Leaves are mostly basal and alternate along the stem, petiolate, with petioles 3 to 10 cm long. Blades are lanceolate to ovate-lanceolate, 5 to 15 cm long and 2 to 6 cm wide, often deeply lobed or toothed, covered with a dense layer of fine, silvery hairs that give the plant a distinctive silvery-gray appearance. The flowers are arranged in coiled cymes and bloom from May through August. Each flower has five fused sepals forming a calyx 3 to 5 millimeters long and about 1.5 to 2 millimeters wide, covered with fine hairs. The corolla is bell-shaped to funnel-shaped, pale blue to lavender, about 10 to 15 mm long and 6 to 10 mm wide, with five lobes at the mouth. The flower contains five stamens with prominent yellow anthers that extend beyond the corolla. The pistil has a superior ovary with a style about 6 to 8 mm long ending in a bifid stigma. The fruit is a small capsule containing several seeds. Silverleaf phacelia is native to South Dakota and is typically found in dry, open habitats such as prairies, rocky slopes, and sandy or gravelly soils, mainly in the western and central parts of the state.

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  Brassicaceae: Alliaria petiolata

  R Neil Reese

  Alliaria petiolata is a biennial herb with a slender, white taproot with occasional fibrous side roots. In the first year, plants form a basal rosette of kidney- to heart-shaped leaves with scalloped edges, each 5–12 cm wide and attached by long petioles. In the second year, the plant produces an erect, simple or occasionally sparingly branched stem, generally 30–100 cm tall, with sparse, fine pubescence on young stems and leaves. Cauline leaves are alternate, triangular to heart-shaped, coarsely toothed, and decrease in size up the stem. The blades are shiny green, hairless or somewhat hairy. The leaves smell like garlic when crushed. The inflorescences are round clusters of a few to several white flowers. Flowering occurs from April to June, with small, white, four-petaled flowers arranged in terminal racemes. Each flower has 4 sepals (green, 2–3 mm), 4 white petals (5–6 mm, narrowly oblong), 6 stamens (4 long and 2 short), and a single compound pistil with a slender style and capitate stigma. Fruits are slender siliques, 3–6 cm long, linear, and green maturing to brown, containing numerous small, oblong, pale brown seeds (2–3 mm). Garlic mustard is a biennial species introduced to South Dakota and is considered invasive; it inhabits woodlands, forest edges, shaded roadsides, and disturbed soils, and has been reported primarily in the eastern and southeastern regions and along river corridors.

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  Brassicaceae : Arabis glabra

  R Neil Reese

  Arabis glabra is a biennial herb growing from a stout taproot. The stem is erect usually unbranched toward the base and branching near the top, growing from 60 to 120 cm tall. The basal leaves are spatulate to oblanceolate, entire to dentate and 5-12 cm long by 1-3 cm wide. The cauline leaves are sessile, lanceolate, entire to denticulate and variable in size (2-10 cm by 1-3 cm) with smaller leaves toward the top. The small flowers are arrayed in racemes and greenish white to yellow in color. The 4 sepals are membranous 2-5 mm long, rounded to subacuminate. The petals are 2.5-6 mm long . the fruit is a cylindrical silique 5-10 cm long and 0.8-1.3 mm wide, with pedicels that are erect or appressed and 7-18 mm long at maturity. The seeds are in 1-2 rows and are about 1 mm long and 0.15 mm wide. Tower rockcress grows in dry prairies on ledges and the edges of woodlands, blooming in May and June. It is much more common in the western side of South Dakota.

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  Brassicaceae: Arabis holboellii

  R. Neil Reese

  Arabis holboellii is a short-lived perennial or biennial herb. The plant forms a narrow taproot system. Stems are generally 15 to 40 centimeters tall, erect, slender and may be branched or unbranched and covered with fine, branched or 2-rayed hairs. Basal leaves are linear to spoon-shaped or narrowly oblanceolate, 1–5 cm long, with toothed margins and pointed tips, and are densely hairy. Cauline leaves are narrower, lance-shaped, and auriculate-clasping, also with fine hairs. Petioles are short (about 0.5 to 1.5 centimeters). Flowering occurs mid to late spring. The inflorescence is a raceme. Flowers have four sepals (2–4 mm, green or purplish), four petals (5–9 mm, white to purple), six stamens (anthers yellow), and a single compound pistil with a slender style and two-lobed stigma. The fruit is a slender, straight to slightly curved silique, 3–8 cm long, 1.5–2 mm wide, maturing in summer and turning brown. Each fruit contains numerous small, brown seeds. Holboell's Rockcress is native to South Dakota. It typically grows in open, rocky, or sandy soils, grasslands, prairies, and open woodlands, occurring statewide but more commonly in the western and central regions.

  Synonym: Boechera holboellii

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  Brassicaceae: Berteroa incana

  R. Neil Reese

  Berteroa incana is an annual or biennial herb with a taproot system, reproducing exclusively by seed. The plant has a simple to much-branched stem, 20–80 cm tall, covered throughout with dense, stellate (star-shaped), grayish-white hairs that give it a distinctive hoary or silvery appearance. Leaves are alternate, simple, lanceolate to oblong, 2–6 cm long, with entire margins and covered in soft, white hairs; the lower leaves are somewhat wider and may have short petioles, while upper leaves are narrower and sessile. Flowering occurs from late spring to summer, with racemes of small, four-petaled white flowers about 8 to 12 millimeters in diameter. Each flower has four white petals approximately 4 to 6 millimeters long and 2 to 3 millimeters wide and four green sepals about 3 to 5 millimeters long. Six stamens are present, with tetradynamous arrangement (four long, two short), featuring slender filaments and yellow anthers. The pistil consists of a single superior ovary with two fused carpels, a slender style, and a bifid stigma. Fruit is a flattened silicle, typically 1 to 1.5 centimeters long and about 5 to 8 millimeters wide, containing multiple small seeds arranged in two rows. Fruits mature in mid to late summer, turning from green to brown as it matures and splits open to release several small, brown, oval seeds. Hoary Alyssum is introduced and considered a noxious weed in South Dakota, particularly in disturbed soils, roadsides, pastures, and waste areas, and it occurs statewide but is most problematic in eastern and central regions.

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  Brassicaceae: Descurainia pinnata

  R. Neil Reese

  Descurainia pinnata is an annual or short-lived perennial herbaceous plant growing from a fibrous root system, typically 10 to 60 centimeters tall, with slender, often branched stems, often covered with soft, spreading hairs. Leaves are alternate, pinnately divided or deeply lobed into thread-like, narrow segments with short and inconspicuous petioles.; basal leaves are larger, up to 10 cm long, deeply divided with linear lobes 1–3 mm wide, while upper leaves are smaller and less divided, usually 2 to 6 cm long. Flowers are small, yellow, arranged in loose racemes blooming from spring through late summer (April–August). Each flower is about 3 to 5 millimeters in diameter, with four yellow petals roughly 1.5 to 3 millimeters long and 0.7 to 1.5 millimeters wide, and four green sepals approximately 2 to 3 millimeters long and 0.5 to 1 millimeter wide. There are six stamens per flower, four longer and two shorter (tetradynamous), inserted around the superior ovary. The pistil consists of a single ovary with a slender style and a capitate stigma. The fruit is a slender, curved silique about 15 to 40 millimeters long and 1 to 2 millimeters wide, containing numerous small seeds. Fruits mature from mid to late summer. Western tansymustard is native to South Dakota and grows in disturbed soils, dry prairies, roadsides, sandy or gravelly sites, and open woodlands statewide.