13. Section Hymenochlaenae (Drejer) L.H. Bailey

Plants monoecious, the rhizomes absent, poorly developed, or short- to somewhat longer-creeping, but with closely spaced stems and leaves, forming tufts or dense to somewhat looser clumps. Vegetative stems absent or present, if present then reduced to basal clusters of leaves or well developed and leafy. Flowering stems erect to loosely ascending, bluntly to sharply trigonous, glabrous, shorter than to longer than the leaves. Leaves basal and on the basal half of the stems, glabrous or hairy. Leaf sheaths with the tip concave or truncate, the ligule shorter than to longer than wide. Spikes 3–7 per stem, the uppermost 1–3 spikes staminate or pistillate toward the tip and staminate toward the base, the remaining lateral spikes mostly pistillate, the bracts leaflike, with well-developed or sometimes very short sheaths. Pistillate spikes mostly well spaced along the axis, sessile to long-stalked, ascending to commonly spreading or drooping, linear to narrowly oblong in outline, with numerous perigynia. Perigynia ascending, sharply trigonous to circular in cross-section, variously shaped and nerved, glabrous. Styles withering during fruit development, jointed to the main body of the fruit, which is minutely beaked at maturity. Stigmas 3. Fruits elliptic to obovate in outline, trigonous. About 65 species, North America, Central America, Europe, Asia, Africa.

The section Hymenochlaenae includes a morphologically diverse assemblage of taxa. The species are mostly distinctive and easily recognized. Several species groups are sometimes segregated from the section, including the Gracillimae (J. Carey) Kük., Longirostres Kük., and Sylvaticae Boott. They differ primarily in details of perigynium shape.