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  Caprifoliaceae : Viburnum lentago

  R. Neil Reese

  Viburnum lentago is a perennial, multi-stemmed tall shrub or small tree, 2-5 m tall and forming colonies from root suckers. Young stems usually have smooth, gray to reddish brown bark, and on older stems the bark becomes dark gray with deeply checkered furrows. The simple, opposite leaves have long winged petioles (10-30 mm) with stellate reddish-brown hairs at the base. The blades are ovate to broadly elliptic, 5-9 cm long and 3-6 cm wide, the tips pointed, the margins finely toothed, the upper surface dark green and shiny and the lower surface paler. The umbel-like inflorescences are 5-12 cm across sessile at the ends of 1-year old branches. Each flower has a tubular calyx with 5 short lobes and a white, bell to saucer shaped, 5-lobed corolla that is 2.5-3.5 mm long. The 5 stamens are exserted from the corolla. The fruit are dark blue-black, flattened, globose drupes, 10-14 mm long, pulpy with a whitish, waxy coating, each containing a large, flat, yellowish seed. Nannyberry blooms in May and June in open woods, along streambanks and occasionally in ditches in the eastern and western counties of South Dakota.

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  Caryophyllaceae: Cerastium arvense ssp. strictum

  R Neil Reese

  Cerastium arvense ssp. strictum is a sprawling, mat-forming perennial herb, the flowering stems erect, 5-30 cm tall, with short simple to glandular hairs throughout. The small, simple, opposite, entire leaves are linear to narrowly oblong, 7-30 mm long and 1-5 mm wide on the flowering branches and generally smaller on the sprawling lateral branches. The inflorescence consists of terminal cymes with a 1-20 flowers on pedicels 5-30 mm long that generally curve downward as they age. The 5 green lance-elliptic sepals are 4-6 mm long and covered with glandular hairs. The petals are 1.5 to 2 times as long as the sepals, deeply cleft, white with grayish streaks and a yellowish throat. There are 10 stamens and 5 styles on the ovary. The fruit is initially a globose capsule that becomes cylindrical, 6-10 mm long when ripe. Prairie chickweed blooms from June to August in prairies, pastures and meadows in the northeastern corner and western edge of South Dakota.

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  Celastraceae : Celastrus scandens

  R. Neil Reese

  Celastrus scandens is a perennial climbing woody vine with twisting stems that reach up to 18 m long. The plants are dioecious, being either male or female, and spread vegetatively by root suckers. The simple, alternate leaves have petioles 1-3 cm long with short stipules (~1 mm). The blades are elliptic to ovate-oblong 3-10 cm long with a pointed tip and the margins are finely toothed. The greenish, unisexual flowers are borne in narrow racemes or panicles which are 3-8 cm long. The flowers are 5-merous with a cup-shaped calyx, 2-3 mm long, united at the base and spreading petals that are 3-6 mm long. Male flowers have 5 stamens, while female flowers have a single 3-parted ovary. Fruit is an orange or yellowish 3-valved capsule, 8-12 mm in diameter, that splits to expose the fleshy bright orange to red aril-covered seeds. There are 1-2 reddish brown seeds in each locule, elliptical in shape and 5-6 mm long. Bittersweet blooms from May to July in woodlands, thickets and along fence rows in much of South Dakota.

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  Chenopodiaceae: Chenopodium berlandieri

  R Neil Reese

  Chenopodium berlandieri is an erect to ascending, unbranched to highly branched herb, mostly < 1 m tall, the stems with green to red to purple stripes and a sparse to dense white-mealy covering, especially on the upper stems. The simple alternate leaves are thick, 2-15 cm long, up to 8 cm wide, variable in shape, diamond-shaped to triangular to oval to lance-elliptic, the tip pointed to blunt, the margins with irregular teeth, the base wedge-shaped to straight, with petioles up to 8 cm long and a white-mealy covering. The lower leaves are largest, irregularly toothed, usually with a pair of shallow lobes near the base. The upper leaves become smaller and less toothy as they ascend the stem, with the uppermost leaves often much narrower and toothless. The inflorescence consists of terminal and axillary panicles of clusters of tiny flowers (glomerules). The flowers have 5 keeled sepals, that are covered with white-mealy dots, and surround the mature fruit. There are 5 stamens and a pistil with 2 styles. The fruit is a dry seed enclosed in the persistent sepals (utricle), arranged horizontally, and having a pitted surface. Pitseed goosefoot blooms from July into September on disturbed, open ground throughout South Dakota.

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  Chenopodiaceae: Chenopodium simplex

  R Neil Reese

  Chenopodium simplex is an erect annual herb. usually having a single stem with spreading branches growing up to 2 m tall. The simple, alternate leaves are thin, triangular to broadly ovate, 7-20 cm long 5-15 cm wide, with 1-5 irregular, large, sharply pointed lobes separated by broad, rounded sinuses. The lower leaves are largest with petioles up to about 2.5 cm long and the upper leaves are usually smaller with shorter petioles. The leaf surfaces are bright green, smooth, sometimes with a sparse, white-mealy covering when young but becoming smooth with age. The inflorescence is a terminal, compact panicle of small clusters of tiny flowers that becomes spread out at maturity. The flowers have 5 sepals, 5 stamens and a pistil with 2 styles. Within a cluster, the flowers may develop at varying rates with some just budding when others have maturing fruit. The fruit are 1-seeded, inflated, lens shaped pods (utricles), 1.5-2.5 mm in diameter. Mapleleaf goosefoot blooms from June into September in sandy and rocky soils in shaded woodlands and disturbed ground throughout much of South Dakota.

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  Cirsium arvense: Cirsium arvense

  R. Neil Reese

  Cirsium arvense is a perennial herb. It grows from a deep, extensive, creeping root system with horizontal rhizomes, enabling vigorous asexual reproduction and the formation of dense colonies. The erect stems are slender, ribbed, and mostly unbranched (except near the inflorescence), typically ranging from 30–120 cm tall, and sparsely hairy to nearly glabrous. Leaves are alternate and lanceolate to linear-lanceolate, typically 5–30 cm long and 2–7 cm wide, deeply lobed, with irregularly toothed margins tipped by sharp yellowish spines; upper leaf surfaces are green and nearly smooth, while the lower surfaces are paler and may be thinly hairy. Both basal and cauline leaves are well developed; basal leaves are often larger and may wither by flowering time. Flowering occurs from mid-June to September. The inflorescences are clusters of small (1–2 cm) heads at the ends of stems and branches. Plants are dioecious, with male and female flowers on separate plants. Flower heads are egg-shaped, each with a series of overlapping green to purplish spiny involucral bracts, which are ovate-lanceolate and sharply pointed. The corollas are composed only of tubular disc florets, 15–20 mm long, with petals that are deeply divided into about five lobes at the tip, giving the corolla a frilled appearance and typically lavender to pink (sometimes white), fragrant, and with long, deeply lobed styles. Male heads produce pollen, while female heads are seed-producing. The fruit is a small, brownish, ribbed achene (2–4 mm) with a tuft of white, hairlike pappus for wind dispersal, maturing from late summer into fall. Canada thistle is an introduced, aggressive noxious weed in South Dakota, invading prairies, cropland, pastures, roadsides, disturbed sites, and riverbanks. It is statewide, particularly abundant in moist, disturbed soils and perennial cropping systems.

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  Clusiaceae: Hypericum perforatum

  R. Neil Reese

  Hypericum perforatum is a perennial herbaceous plant typically reaching heights of 30 to 90 cm. The plant has a fibrous root system and may spread by creeping rhizomes. Its stems are erect, square in cross-section, and usually glabrous or sparsely hairy with a reddish tint. The leaves are opposite, simple, narrow to oblong-lanceolate in shape, measuring approximately 1.5 to 4 cm long and 0.5 to 1.5 cm wide. Leaf margins are entire, and the leaf surfaces are smooth with characteristic tiny translucent glands that appear as perforations when held to light. Leaves are sessile and stipules are absent. The inflorescence usually forms in loose clusters (cymes) that bloom from late spring through summer (June–August). Flowers are about 1.5 to 2.5 cm in diameter, with five lanceolate to ovate sepals measuring 6 to 10 mm long and 2 to 4 mm wide, often marked by tiny black dots along the margins, and five bright yellow obovate petals approximately 1 to 1.5 cm long and 5 to 8 mm wide. The flowers contain numerous stamens, typically 30 to 60, grouped into three to five bundles. The pistil consists of three styles arising from a superior ovary, each ending with a stigma. The fruit is a small, ovoid to ellipsoid capsule approximately 5 to 8 mm long that splits open at maturity to release numerous tiny seeds Common St. John’s wort is native to Europe and parts of Asia, and is commonly found in South Dakota in disturbed areas, grasslands, roadsides, and open woods.

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  Commelinaceae : Tradescantia bracteata

  R. Neil Reese

  Tradescantia bracteata is a subsucculent perennial herb with erect to ascending, simple or occasionally branching stems, with 2-4 nodes and growing 5–45 cm tall. The stems can have a zig-zag appearance due to the jointed leaf attachment and multiple stems often emerge from an underground crown. The simple, alternate leaves are green with a whitish waxy coating, linear-lanceolate, 8-30 cm in length and 7-16 mm wide, rarely folded, with sheathing bases and entire margins. The inflorescence is an umbellate cyme of few to many flowers at the top of the stem, and at the ends of branches arising from leaf axils, with only 1 to a few open at a time and subtended by elongated bracts similar to the foliage leaves, 6-30 cm long. Flower pedicels are 2–3 cm long with glandular and non-glandular hairs. The 3 sepals are 10-13 mm long with glandular hairs and purplish margins. The 3 petals are broadly ovate, about 18 mm long and blue to rose-violet in color. The flowers open in the morning and typically wilt by noon. There are 6 stamens with bright yellow anthers and long blue hairs toward the base of the filaments. The fruit is a rounded capsule with three locules, each producing 1- few oblong seeds, 2-4 mm long. Long-bracted spiderwort blooms from May through August, growing on moist disturbed soils throughout South Dakota.

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  Commelinaceae : Tradescantia occidentalis

  R. Neil Reese

  Tradescantia occidentalis is a subsucculent perennial herb with erect, simple or occasionally branching stems, with 2-6 nodes and growing to 60 cm tall. The stems can have a zig-zag appearance due to the jointed leaf attachment. The simple, alternate leaves are green with a whitish waxy coating, linear-lanceolate, 9-33 cm in length and 4-15 mm wide, often folded, with sheathing bases and entire margins. The inflorescence is an umbellate cyme of few to many flowers at the top of the stem, and at the ends of branches arising from leaf axils, with only 1 to a few open at a time and subtended by elongated bracts similar to the foliage leaves, 6-20 cm long. Flower pedicels are 1-2 cm long with glandular hairs. The 3 sepals are 8-13 mm long with glandular hairs and purplish margins. The 3 petals are broadly ovate, 7-15 mm long and blue to rose in color. The flowers open in the morning and typically wilt by noon. There are 6 stamens with bright yellow anthers and long blue hairs toward the base of the filaments. The fruit is a rounded capsule with three locules, each producing 1- few oblong seeds, 2-4 mm long. Prairie spiderwort blooms from May through August, growing on sandy disturbed soils in western and northeastern South Dakota.

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  Convolvulaceae: Calystegia sepium ssp. angulate

  R Neil Reese

  Calystegia sepium ssp. angulate is a rhizomatous, perennial vining herb growing up to 4-5 m in length, the stems smooth and lacking tendrils, wrapping around plants and fences for support. The simple, alternate leaves are arrowhead shaped, the petioles are 2-7 cm long, and the blades are 2-15 cm long by 1-9 cm wide. The margins are entire to wavey. The axillary flowers are solitary on peduncles 3-13 cm long with 2 angular, somewhat inflated bracts, 14-26 mm long and 10-18 mm wide, surrounding the calyx. The 5 rounded, unequal sepals are 11-15 mm long by 4-6 mm wide, thin and somewhat transparent. The funnel shaped corolla is white, often tinged with pink on the edges, 4.5-6 cm long and about as wide at the opening. There are 5 subequal stamens 2.5-3 cm long and the style is about 2.5 cm long. Each flower usually lasts only 1 day. The fruit is a capsule, 10-13 mm in diameter and surrounded by the enlarged bracts that can reach 3.5 cm in length. Hedge bindweed blooms from June into August in thickets, atop fences and hedges throughout South Dakota.

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  Convolvulaceae: Convolvulus arvensis

  R Neil Reese

  Convolvulus arvensis is a rhizomatous, perennial, widely spreading, decumbent to vining herb with multiple stems growing up to 2 m in length, the stems smooth and lacking tendrils, lying on the ground or wrapping around plants and fences for support. The simple, alternate leaves are variable, ovate to heart shaped to arrowhead shaped, the petioles are 3-40 mm long, and the blades are 1-10cm long by 0.3-6 cm wide, the margins are entire to wavey, the lobes sometimes with 2-3 teeth. The axillary flowers are solitary or with 2-3 flowers on peduncles 1-9 cm long and pedicels 5-18 mm long. Each flower is subtended with 2 linear to elliptic bracts, < 1 cm long and about 2-3 cm below the flower. The 5 rounded, unequal sepals are 3-5 mm long by 2-5 mm wide, the inner ones largest, smooth to hairy. The funnel shaped corolla is white, often tinged with pink, with a yellow patch at the base, 12-25 mm long and about as wide at the opening. The 5 lobes of the corolla are very shallow. There are 5 stamens and a pistil with a divided style that are white, except the anthers that are often purple. Each flower usually lasts only 1 day. The fruit is a round to ovoid capsule, 5-7 mm in diameter. Field bindweed blooms from June into August in in disturbed ground throughout South Dakota.

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  Convolvulaceae : Ipomoea leptophylla

  R. Neil Reese

  Ipomoea leptophylla is a long-lived perennial shrub-like herb, with multiple smooth, decumbent to erect, stems, from a single large root, that grow 30-120 cm in length. The plant develops a large spindle shaped tuber that can extent more than 2 m into the ground and weigh up to 45 kg. The simple, alternate leaves are linear to linear-lanceolate, 3-15 cm long and 2-8 mm wide, petioles 1-7 mm long, the margins entire with a sharp tip. The inflorescence consists of axial cymes of 1-3 (rarely more) on long (7-10 cm) peduncles and each flower having a pedicel of 5-10 mm. The sepals are unequal in size, 5-10 mm long, the inner ones longer and wider than the outer. The purple to pink petals are fused, funnel shaped, 5-9 cm long with a darker throat. The stamens are included, unequal in length, 2-3 cm long with anthers 5-7 mm long. The pistil has a smooth, ovoid ovary and the style is included in the corolla. The fruit is an ovoid capsule 1-1.5 cm long. The seeds are large, 10 mm long and 4 mm wide, with a fine downy-haired coating. Bush morning glory blooms from May through September in the sandy plains and prairies of southwestern South Dakota.

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  Cornaceae: Cornus drummondii

  R. Neil Reese

  Cornus drummondii is a deciduous shrub or small tree reaching 3 to 7 meters tall. The bark is grayish-brown and becomes deeply furrowed and scaly with age. Roughleaf dogwood is characterized by stiff, rough-textured leaves that are opposite, simple, ovate to elliptical, typically 7 to 12 centimeters long and 3 to 6 centimeters wide, with petioles 1 to 2.5 centimeters long, with prominent veins and a slightly hairy underside. The margins are entire to slightly wavy. Flowering occurs in late spring (May to June) with flat-topped cymes of small, creamy white flowers about 5 to 7 millimeters in diameter. Flowers have four petals approximately 2 to 3 millimeters long and 1 to 1.5 millimeters wide and four green sepals about 1.5 to 3 millimeters long. There are eight stamens inserted around the superior ovary, with filaments about 2 to 4 millimeters long and small, yellowish anthers. The pistil is composed of a single ovary with a slender style and a slightly lobed stigma. The fruit is a globose, white to cream-colored drupe about 8 to 10 millimeters in diameter that matures from late summer into early fall. Roughleaf dogwood is native to the central United States and occurs in eastern South Dakota, typically in upland woods, prairies, and along streams.

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  Cornaceae : Cornus sericea

  R. Neil Reese

  Cornus sericea is a perennial branching stoloniferous, thicket-forming shrub, growing to 3 m in height. The stems have reddish bark, young branches with short, stiff hairs and older branches smooth. The simple, opposite, petiolate leaves are oblong-lanceolate to ovate, 3–15 cm long, 2-5-5.5 cm wide, with a pointed tip and with 5-7 pairs of prominent pennate veins that are curved toward the tip. The upper surface is green with a few hairs and the lower surface paler. When pulled apart, the veins produce white web-like strands. The inflorescences are flat-topped compound cymes, 3–10 cm across. The sepals are minute, the 4 white to cream colored petals are 2-4 mm long, attached to a disk, the ovary inferior and the stamens as long or longer than the petals. The fruit is a 1-2 seeded drupe, 6-9 mm in diameter. Red osier dogwood blooms from May through July along stream banks, lakeshores and in swampy wet places throughout South Dakota.

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  Cucurbitaceae: Echinocystis lobata

  R. Neil Reese

  Echinocystis lobata is an annual, fast-growing, climbing vine from a fibrous root system that can reach lengths over 6 meters, with tendrils that help it climb shrubs and fences. Stems are slender, green to reddish, and covered with fine hairs and small prickles. Leaves are alternate, palmately lobed with 5–7 deeply cut lobes, 8 to 18 cm long and wide, broadly ovate with coarsely toothed margins and a rough, hairy texture. The petioles are about 6 to 15 centimeters long. Flowering occurs from June to September, producing small, white to pale greenish flowers in leaf axils. Flowers are unisexual and monoecious, with male flowers in open clusters and female flowers solitary or few. Each flower has five greenish-white sepals about 5 to 8 millimeters long and no true petals; instead, the sepal lobes form petal-like structures. Male flowers have numerous stamens fused into a column with anthers around 1 to 2 millimeters long. Female flowers have a single superior ovary with three styles ending in clustered stigmas. The fruit is a spiny, inflated capsule about 4 to 6 centimeters long and 3 to 5 centimeters wide, covered with hooked prickles, maturing in late summer to early fall and splitting open to release numerous seeds. Wild cucumber is native to South Dakota and is commonly found in moist woods, riverbanks, thickets, and edge habitats statewide.

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  Cupressaceae: Juniperus communis

  R Neil Reese

  Juniperus communis is a low, spreading evergreen shrub, growing to 1.5 m high, often forming clumps. The young twigs are yellowish and 3-angled and older stems becoming grayish and finally reddish brown with shredding papery bark. The leaves are needle-shaped, waxy, 10-18 mm long, up to 1.5 mm wide, in whorls of 3 and curved sharply just above the base. The plants are dioecious with axillary, sessile pollen-bearing cones that are and mostly single, 3-5 mm long and 1-2 mm wide being produce on male plants. Female plants produce seed cones that are fleshy, dark blue with a waxy bloom, globose, 5-10 mm in diameter, maturing in the second year and contain 1-3 brown seeds. New cones are pollinated in May and June, usually on wooded hillsides in western South Dakota.

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  Cupressaceae : Juniperus virginiana

  R. Neil Reese

  Juniperus virginiana is a perennial, non-flowering, coniferous evergreen tree with a pyramidal or subcylindrical shaped crown, growing 5–20 m in height. The bark is reddish-brown to gray, fibrous and shredding as it ages. The younger branches are usually red. The adult leaves are green to blue green, tightly adpressed and scale-like, 2–4 mm long, 0.8-1.5 mm wide, arranged in opposite decussate pairs or occasionally whorls of three and overlapping the leaves above. Juvenile leaves are needle shaped, 5–11 mm long and are present on young trees and new branches. Red cedar is usually dioecious with male plants having yellowish-brown, sessile, solitary ovoid cones, 2.5-4 mm long, 1-2 mm in diameter, attached to the ends of branchlets. Female trees produce solitary, berry-like seed cones that are 3–7 mm in diameter, dark purplish-blue with a white waxy covering. These cones mature during the first year and contain 1-3 yellowish seeds. Cones shed pollen and are fertilized in April and May. Eastern red cedar is native to southern South Dakota, being found on pastures, prairie hillsides and disturbed ground. Because of its wide use in shelter belts, it has escaped and is naturalized throughout SD.

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  Cyperaceae: Carex brevior

  R. Neil Reese

  Carex brevior is a perennial sedge in the Cyperaceae family. It grows from a dense, fibrous root system with short rhizomes, sometimes forming small clumps but not extensive sods. The stems (culms) are upright, slender, triangular in cross-section, and usually 30–70 cm tall, smooth or minutely rough below the inflorescence. Leaves are mostly basal, grass-like, flat, and 2–5 mm wide, with sheathing bases and rough margins. Cauline leaves are few, shorter than the culms, and often drooping. Flowering occurs from late spring to early summer (May–July). Inflorescences are terminal, composed of 2–5 short, dense, cylindrical spikes. The terminal spike is usually staminate (male), while the lower spikes are pistillate (female), but sometimes spikes are androgynous. Each spike is 1–3 cm long and 5–7 mm wide. Each pistillate flower is enclosed in a sac-like perigynium, which is green to brown, inflated, and beaked. The perigynia are 3–5 mm long and 1–2 mm wide, with a short, thick beak. The achene (seed) is lens-shaped, brown, and 1.5–2 mm long, maturing in early to midsummer. Shortbeak sedge is native to South Dakota, occurring in dry to mesic prairies, open woodlands, roadsides, and disturbed soils, and is found statewide, especially in upland prairies and open meadows.

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  Cyperaceae: Carex hoodii

  R. Neil Reese

  Carex hoodii is a perennial sedge in the Cyperaceae family. It grows from a dense, fibrous root system with short rhizomes, forming loose tufts or small clumps rather than extensive sods. Stems (culms) are upright, slender, sharply three-angled, and range from 20–60 cm tall, smooth below but often rough near the inflorescence. Leaves are mostly basal, narrow, flat or slightly folded, 1–3 mm wide, and shorter than the culms, with rough margins and tight basal sheaths. Flowering occurs from late spring to mid-summer (May–July). Inflorescences are terminal and consist of 2–4 short, narrow spikes (each 1–2.5 cm long). The terminal spike is commonly staminate (male), while the lower spikes are pistillate (female), though some spikes may be androgynous. Pistillate flowers are enclosed in a sac-like perigynium, which is green to brown, ovoid to ellipsoid, 2.5–4 mm long and 1–1.5 mm wide, with a short, straight beak. The achene (seed) is lens-shaped, brown, and about 1.5 mm long, maturing in early to mid-summer. Hood’s sedge is native to South Dakota, typically found in dry to mesic prairies, open pine woods, rocky slopes, and sandy soils, and is most frequent in the Black Hills, Coteau des Prairies, and northern and western uplands.

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  Cyperaceae: Carex muehlenbergii

  R. Neil Reese

  Carex muehlenbergii is a perennial sedge growing from a fibrous root system with slender, short rhizomes, forming loose tufts but not dense sods. Stems (culms) are upright, sharply three-angled, and range from 20–60 cm tall, usually smooth or sometimes slightly rough near the inflorescence. Leaves are mostly basal, narrow (1–3 mm wide), flat or slightly folded, and shorter than or about equal to the culms, with rough margins and sheathing bases. The ligule is a thin, translucent band about 1 to 2 millimeters high, often acute and sometimes with frayed edges. Flowering occurs from late spring to early summer (May–July). The terminal inflorescence consists of 2–5 short, cylindrical spikes, with the top (terminal) spike usually staminate (male) and lower spikes pistillate (female), though some may be androgynous. Each flower has scale-like bracts subtending small florets. Stamens number three with slender filaments and pollen-bearing anthers; the pistil has a single ovary with one style and two branching stigmas. Pistillate flowers are enclosed in a sac-like perigynium, which is green to brown, ovoid, 2.5–4 mm long and about 1 mm wide, with a short, straight beak. The achene (seed) is lens-shaped, brown, and about 1.5 mm long, maturing in early to midsummer. Sand sedge is native to South Dakota, most commonly found in dry, sandy prairies, open woodlands, sand dunes, and disturbed sandy soils, and is widespread but especially abundant in sandy uplands and the central and western parts of the state.

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  Cyperaceae: Carex praegracilis

  R. Neil Reese

  Carex praegracilis is a perennial sedge in the Cyperaceae family. It grows from a dense, fibrous root system with long, creeping rhizomes, forming loose to dense sods and spreading readily by vegetative means. Stems (culms) are upright, slender, sharply three-angled, usually 20–70 cm tall, and smooth or slightly rough near the inflorescence. Leaves arise mostly from the base, with sheathing leaf bases that are smooth and light brown to tan and may be tinged reddish-brown. Leaf blades are narrow and flat, typically 2 to 4 mm wide often shorter than the culms, with rough margins. The ligule is a short, membranous, translucent structure about 1 to 2 millimeters long, often acute or truncate with smooth or slightly jagged edges, located at the junction of leaf blade and sheath. Flowering occurs from late spring to early summer (May–July). Inflorescences are terminal, composed of 2–5 short, cylindrical spikes, slender, erect, bearing numerous small spikelets clustered at the top of the stems. The species is usually monoecious, with staminate (male) flowers in terminal spikelets and pistillate (female) flowers in lateral or lower spikes, though some may be androgynous. Floral scales subtend florets with three stamens in male flowers and a single ovary with one style (dividing into two stigmas) in female flowers. Pistillate flowers are enclosed in a sac-like perigynium, which is green to brown, 2.5–4 mm long, and about 1 mm wide, with a short, straight beak. The achene (seed) is lenticular, brown, and about 1–1.5 mm long, maturing from early to midsummer. Clustered field sedge is native to South Dakota, commonly found in moist to wet meadows, prairies, roadside ditches, alkaline flats, and disturbed soils. It is distributed statewide but is especially abundant in low, moist sites and along roadsides.

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  Cyperaceae: Cyperus odoratus

  R. Neil Reese

  Cyperus odoratus is an annual or short-lived perennial sedge with a fibrous root system and sometimes tuberous rhizomes, allowing moderate vegetative spread. The erect stems (culms) are slender, triangular in cross-section, and range from 10 to 80 cm tall. Leaves are grass-like, alternate, linear, and smooth to rough, typically 5–30 cm long and 2–5 mm wide, with rough margins and sheathing bases that wrap closely around the stem base. The ligule is short and inconspicuous, often appearing as a small fringe of hairs or a thin membrane. Flowering occurs from summer through fall (June–October). Inflorescences are compound umbels with multiple rays, each bearing clusters of small spikelets. Spikelets are lanceolate to ovate, 2–5 mm long and consist of many brown to purplish-brown flowers covered by overlapping scales. Flowers have three stamens and a pistil with three stigmas. The fruit is a small, lens-shaped achene, about 1–2 mm long, brown at maturity, ripening from late summer into fall. Fragrant flatsedge is native to South Dakota, occurring in wetlands, marshes, ditches, riverbanks, and moist disturbed soils statewide, with higher concentrations in eastern and central regions.

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  Cyperaceae: Eleocharis compressa

  R. Neil Reese

  Eleocharis compressa is an annual to perennial herbaceous sedge from a fibrous root system. Stems (culms) are erect, slender, and usually laterally compressed (flattened) in cross-section, ranging from 10–50 cm tall. Leaves are reduced to narrow sheaths at the base of the stem, with no true leaf blades. The ligule is typically absent or represented by a small membrane or fringe of hairs at the junction of sheath and stem. Flowering occurs from summer to early fall (July–September). The inflorescence consists of a single terminal spikelet about 5–15 mm long, narrow and cylindrical, containing numerous tiny flowers. Each flower is subtended by a scale (a modified bract) about 2–3 mm long, ovate to lanceolate in shape, greenish to brownish in color. Flowers have no petals or sepals but possess three stamens and a single pistil. The fruit is a small, lens-shaped achene, about 1–2 mm long, brown at maturity, ripening late summer into fall. Flat-stem spike-rush is native to South Dakota, commonly occupying wetlands, shallow ponds, marshes, and wet meadows statewide, especially in the eastern and central regions.

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  Dennstaedtiaceae: Pteridium aquilinum

  R. Neil Reese

  Pteridium aquilinumis a large, perennial fern spreading by extensive underground rhizomes and forming dense colonies. Fronds are alternate, compound, grow 50 to 150 cm tall, are triangular and deeply pinnatifid, with a leathery texture. Leaflets are lanceolate, typically 3–8 cm long and 1–3 cm wide, with serrated margins. Petioles (stipes) are erect, reddish-brown to dark brown. Length varies but can be up to 1 meter and are covered in fine hairs or scales near the base. The upper surface of the leaflets is medium green and smooth, while the lower surface is paler and bears sori (spore-producing structures) arranged in two rows along the underside of the pinnae margins. The sori are covered by indusia that are kidney-shaped, about 2–3 mm wide. The fern reproduces by spores released from mature sori, typically in late summer to early fall (August to October). Native to South Dakota, bracken fern primarily distributed in the Black Hills region in the western part of the state, thriving in a variety of habitats including woodlands, open fields, roadsides, and disturbed sites, often preferring acidic, well-drained soils.

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  Elaeagnaceae: Elaeagnus angustifolia

  R Neil Reese

  Elaeagnus angustifolia is a perennial large shrub or small tree growing to 5 m tall. The trunk and mature branches have a scaly gray-brown bark, with young branches being covered with silvery gray hairs. The small branches often end in sharp spines. The alternate, simple, petiolate leaves are covered with silvery scales are star-shaped hairs. The blades are up to 10 cm long and usually less than 18 mm wide. The inflorescence consists of axillary groups of 1 to 3 short-stalked flowers on the young branches. The fragrant flowers are funnel-shaped, ~12 mm long and wide, with 4 spreading, yellow petal-like sepals that are silvery on the outer side. They are fused at the base and form an angled tube about as long as the lobes. There are 4 yellow stamens and a style. The fruit are edible, but mealy drupe-like achenes. Russian olive flower in May and June ad the fruit ripen in August through October. This species was introduced as a windbreak species and has become naturalized throughout the US. Although still planted for game improvement in some states, it is considered an invasive species in South Dakota.