32. Section Vulpinae (J. Carey) H. Christ

Plants monoecious, with short or poorly developed rhizomes, forming tufts or clumps. Vegetative stems usually poorly developed, mostly reduced to basal clusters of leaves. Flowering stems erect to spreading, shorter than to longer than the leaves, bluntly to mostly sharply trigonous, often narrowly winged, firm (in C. oklahomensis) or more commonly easily crushed, glabrous, somewhat roughened on the angles near the tip, light brown to dark brown at the base. Leaves basal and on the basal half of the stems, glabrous, the basal leaves reduced to persistent, nearly bladeless sheaths. Leaf blades with the margins minutely roughened or toothed, flat or somewhat folded near the base. Leaf sheaths with the ventral side thin, papery, white or nearly so (the tip thickened and yellow in C. laevivaginata), sometimes cross-wrinkled and breaking up at maturity, the dorsal side green or bluish green, the lowermost sheath bases light brown to dark brown. Inflorescences compound with the lower branches short to elongate and well separated along the main axis, the upper portions dense and headlike, with 10 to usually numerous spikes, the bracts shorter than the inflorescences, hairlike, sometimes absent. Spikes sessile or with minute stalks, inconspicuously staminate toward the tip and pistillate toward the base, oblong-elliptic to nearly circular in outline, with 4 to numerous densely spaced perigynia, these ascending to spreading or reflexed at maturity. Staminate and pistillate scales similar, ovate to broadly elliptic-ovate in outline, the tip pointed, sometimes awned, white or light brown to brown, with a green midrib. Perigynia mostly thin-walled, flattened ventrally and somewhat rounded dorsally, lanceolate to ovate-triangular in outline, gradually (or in C. conjuncta abruptly) tapered to a flattened beak with 2 narrow teeth at the tip, the base rounded to truncate, more or less thickened with corky or spongy tissue, the sides angled to narrowly winged, glabrous. Styles withering during fruit development, jointed to the main body of the fruit, which is not or minutely beaked at maturity. Stigmas 2. Fruits ovate to broadly elliptic-ovate in outline, biconvex and somewhat flattened in cross-section, yellowish brown to reddish brown. About 17 species, North America, Europe, Asia, Africa, Australia.

Section Vulpinae shares many features with section Phaestoglochin, but members of that section have inflorescences that have fewer spikes and are almost always simple. Species of Vulpinae have perigynia with the basal portion thickened with spongy tissue that is situated around the base of the achene, which does not fill the base of the perigynium. The perigynia are relatively thin-walled and at maturity the bases often appear puckered or irregularly swollen. Upon drying, the surface of the spongy portion usually develops irregular wrinkles and often turns tan to yellowish brown. Poking the perigynia with a dissecting needle will reveal the white to yellowish white, spongy tissue surrounding the base of the achene.