16. Carex digitalis Willd.

Pl. 33 a–d; Map 129

C. digitalis var. macropoda Fernald

Plants without noticeable rhizomes, forming dense tufts. Vegetative stems with the leaves slightly wider than those of the flowering stems, sometimes somewhat corrugated in cross-section. Flowering stems 7–35(–50) cm long, weak, erect to more commonly spreading, white to light brown at the base. Leaves shorter than to longer than the stems. Leaf blades 8–30 cm long (except on bladeless, basal sheaths), 1–5 mm wide, thin, green, not glaucous, the margins and veins minutely roughened or toothed, flat. Leaf sheaths with the tip deeply concave the lowermost sheath bases white to light brown, sometimes with scattered, small, reddish purple spots. Spikes 2–5 per stem, the bracts leaflike, shorter than to longer than the inflorescence. Staminate spike 10–24 mm long, sessile to long-stalked, not hidden by the bracts of the pistillate spikes. Pistillate spikes 6–20 mm long, 3–4 mm wide, sessile to long-stalked, ascending to spreading or drooping, with 3–9 perigynia, the lowermost scales all with perigynia. Staminate scales 2.0–3.5 mm long, yellowish white to white, with a green midrib and sometimes light brown or faintly reddish purple margins. Pistillate scales 1.8–2.0 mm long, ovate, the tip sharply pointed, yellowish white to white or tan, with a green midrib. Perigynia 2–4 mm long, elliptic-obovate in outline, beakless or nearly so. Fruits 1.8–3.8 mm long. 2n=48. May–July.

Scattered in the Ozark and Ozark Border Divisions and also in portions of the Mississippi Lowlands (eastern U.S. west to Wisconsin and Texas). Mesic to dry upland forests, usually on north- to northwest-facing slopes, often in sandy to rocky soils on acidic substrates; less commonly on ledges of sandstone outcrops and bluffs and along the margins of sinkhole ponds.

Some botanists recognize three varieties of this species (Steyermark, 1963; Bryson, 1980). The weakly defined var. asymetrica Fernald is nearly endemic to the Atlantic and Gulf Coastal Plains, differing from var. digitalis only in its slightly larger perigynia with slightly more nerves. It has not been recorded from Missouri. The other two varieties are fairly distinct through most of their range. The more northern var. digitalis has the staminate spike short-stalked and overtopped by the bract of the sessile (or nearly so) uppermost pistillate spike, as well as having flowering stems mostly shorter than the foliage. The more southern var. macropoda Fernald has a longer-stalked staminate spike not overtopped by the bract of the uppermost pistillate spike and flowering stems mostly longer than the foliage. Missouri is in the zone of overlap between these two varieties, whose recorded distributions within the state are nearly identical, and which frequently grow together in the southern Ozarks. Many specimens from the state are intermediate for one or more of the characters said to differentiate these varieties, and maintaining them in the present treatment would only lead to frustration for users attempting to determine specimens to variety.