1. Bulbostylis capillaris (L.) Kunth ex C.B. Clarke

Pl. 29 e–g; Map 117

B. capillaris var. crebra Fernald

B. capillaris var. isopoda Fernald

Plants annual, tufted. Stems usually several per plant, 5–30 cm long, slender, erect or ascending, unbranched, strongly ribbed, glabrous. Leaves basal and 1–2 along the lower stems. Leaf sheaths with the apices thin, scarious, and with a dense fringe of cobwebby hairs, the ligule absent. Leaf blades 1–11 cm long, less than 0.5 mm wide, spreading to ascending, with usually 5 strongly ridged veins, the margins curled inward, glabrous. Inflorescences terminal, subtended by 2 to several short, leaflike bracts, composed of 2–9 spikelets, these sessile and/or stalked in umbellate clusters, less commonly in headlike clusters or appearing as 1 stalked and 1 sessile spikelet. Spikelets 2–5 mm long, lanceolate to narrowly elliptic in outline, the tips pointed, the florets 6–15 or more, several-ranked in an overlapping spiral pattern. Spikelet scales 1.5–2.2 mm long, ovate, keeled, glabrous or minutely hairy, the margins often irregular or with a cobwebby fringe of fine hairs, dark brown to reddish brown, the green midrib often extended into a short mucro at the tip. Florets perfect. Perianth (bristles or scales) absent. Stamens 2. Styles expanded at the base and persisting at the tip of the fruit as a minute, peglike or caplike tubercle, usually dark brown at maturity and separated from it by a line or constriction. Stigmas 3. Ovaries and fruits naked, without a perigynium (saclike covering). Fruits 0.7–1.0 mm long, broadly elliptic to obovate in outline, strongly 3-angled, the surface with horizontal wrinkles, pale yellow to light brown. 2n=72, 84. June–October.

Scattered but widespread in eastern and southern Missouri, mostly south of the Missouri River (eastern and southwestern U.S., Mexico, Cuba, Asia). Glades, thin-soiled areas of prairies, and rocky openings of dry upland forests, mostly on acidic substrates; also in open, sandy areas, including sand prairie remnants, pond margins, and roadsides.

The small, wispy plants of this species are easily overlooked in the field, particularly the smaller plants that occur on sandstone and igneous glades. In some Missouri populations, short-stalked spikelets are produced at the base of the plants in addition to inflorescences at the tips of more usual stems. Production of such spikelets is sporadic and unpredictable, and the mechanism regulating it is unknown.