Scleria pauciflora and S. triglomerata are perennials with hard culm bases and rhizomes; S. reticularis and S. verticillata are soft based, fibrous rooted annuals.
An additional Coastal Plain disjunct species, S. muhlenbergii, is known from northern Indiana and might be discovered in southwestern Michigan. It is an annual, resembling S. reticularis, but has the lower flower clusters nodding on flexuous peduncles rather than erect on stiff peduncles, and usually pubescent rather than glabrous achenes.
1. Achenes smooth, ca. 3 mm long, including the whitish, foam-like basal disc; larger leaves (3.5–) 5–7.5 mm wide; mature anthers ca. 2.5–4 mm long.
1. Achenes papillose-roughened or wrinkled, ca. 1–2 mm long, including basal disc (not a foam-like crust); larger leaves not over 2.5 mm wide; anthers ca. 1–2.5 mm long.
2. Culms and leaves pubescent; anthers ca. 2–2.5 mm long; flower clusters 1 or 2 (rarely 3) on a culm, each subtended by an elongate leaf or leaf-like bract; disc at base of achene ornamented with 6 ± separate rounded tubercles; perennial with knotty rhizomes.
2. Culms and leaves glabrous or nearly so; anthers ca. 1–1.6 mm long; flower clusters (1–) 3–5, at most, the lowest subtended by an elongate blade; disc at base of achene absent or clearly 3-lobed; annuals from thin, fibrous roots.
3. Flower clusters (at least the lowest) pedunculate, bracteate, disc at base of achene conspicuous, 3-lobed.
3. Flower clusters all sessile, even the lowest lacking a bract; disc at base of achene not tubercled, inconspicuous or apparently absent.