IUCN threat status:

Least Concern (LC)

Comprehensive Description

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Description

This perennial grass is 1½-3' tall, forming a dense erect tuft of flowering culms. Straw-colored remnants of older leaves and culms are usually present while new leaves and culms are developing. Culms of the current year are light to medium green, glabrous or hairy, and terete to slightly flattened; they are largely hidden by the sheaths. Each culm is unbranched below, but it develops short branching culms above where the inflorescence occurs. Alternate leaves occur along the entire length of the culm, although they are more common below. The leaf blades are 3-12" long and 2-7 mm. across; they are erect, ascending, or widely spreading. The leaf blades are dull light to medium green and mostly glabrous, except toward their bases, where long hairs usually occur along their upper sides or margins. Leaf sheaths are dull light to medium green, somewhat inflated, somewhat flattened, and open; they are usually glabrous, although some long hairs may occur along their sides and upper margins. The upper secondary culms develop clusters of 2-4 racemes of spikelets. Individual racemes are ¾-1½" long, erect or ascending, and partially hidden by their sheaths. Along the rachis of each raceme, there are several pairs of spikelets. Each pair of spikelets consists of a sessile spikelet (3-4 mm. long) with a perfect floret and a short pedicel (4-5 mm. long) with an empty (or missing) spikelet; sometimes an awn-like scale (less than 0.5 mm. long) is present at the apex of the pedicel. Each pedicel is covered with long white hairs. At the base of the sessile spikelet, there is a small tuft of white hairs. The sessile spikelet consists of a linear-lanceolate glume, a linear-lanceolate lemma with an awn, and a membranous palea enclosing one side of the floret. Both the glume and lemma are keeled. The slender awn of the lemma is 8-20 mm. long, straight or slightly curved, and not twisted nor sharply bent toward the base. The perfect floret consists of an ovary with a pair of feathery stigmata and a single stamen. The blooming period occurs during late summer or early fall for about 1-2 weeks. The florets are wind-pollinated. Afterwards, fertile florets are replaced by elongated grains about 2.5-3.0 mm. long; the latter are blown about to some extent by the wind. The root system consists of a dense crown of fibrous roots.

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© John Hilty

Source: Illinois Wildflowers

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