16b. ssp. macilentus (Fernald) Marcks

C. filiculmis var. macilentus Fernald

Spikelets 3–8 mm long, with 3–7 florets. Spikelet scales 2.0–2.5 mm long, tightly clasping the fruits. Fruits 1.4–2.0 mm long. 2n=164, ca. 166. May–October.

Scattered in eastern Missouri and locally westward along the Missouri River floodplain (northeastern U.S. locally south to Georgia; Canada). Mesic to dry upland forests, sand prairies, and sandstone glades; also pastures, roadsides, railroads, and dry, open, disturbed ground, usually in acidic substrates with rocky or sandy soils.

This is the less common subspecies in the state. It tends to have the spikelets in very dense spikes, with only the tip of each spikelet visible when fresh, and also commonly has unbranched inflorescences.