IUCN threat status:

Not evaluated

Comprehensive Description

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The vernal form of this perennial grass forms tufts of leafy culms about 12-20" tall (see Vernal Leafy Culm). The erect to ascending culms are light to medium green, softly hairy, and terete; they are partially hidden by the sheaths. Along each culm, there are about 4-5 alternate leaves along the lower 75% of its length. Toward the middle of each culm during the blooming period, there may be 2 or more lateral culms that are leafy and short. Leaf blades along the central culm are 2-4" long, 4-10 mm. across, and ascending to widely spreading. The upper blade surface is medium green or greenish blue, dull, and nearly hairless to covered with long appressed hairs. The lower blade surface is pale to medium green, dull, and evenly short-hairy. The lower margins of each leaf blade are ciliate with long white hairs. The leaf sheaths are pale to medium green, longitudinally veined, and covered with spreading to ascending hairs (both long and short hairs are present). The ligules are 2-5 mm. long; each ligule consists of a short-chaffy membrane and a collar of hairs. The nodes are slightly swollen; they have widely spreading long hairs. The central culm terminates in an exerted panicle of spikelets about 2-3½" long and 2-3" across. This inflorescence has an airy appearance and it is broadly ovoid-pyramidal in shape. Along the central axis of the panicle, there are lateral branches in groups of 1-3 that subdivide into pedicels about 0.5-1.0 cm. long; each pedicel terminates in a single-flowered spikelet. The central axis is slender, medium green, and sparsely hairy, while the slender lateral branches are wiry, hairless, and light to medium green. The lateral branches are ascending to widely spreading and stiff. The spikelets are 2.0-2.5 mm. in length and about one-half as much across; they are light green to purplish green (becoming light tan with age), ovoid-obovoid in shape, and hairy with fine longitudinal veins. Each spikelet consists of 2 glumes, a lemma, and a perfect floret. The shorter glume is about one-third the length of the spikelet and ovate in shape, while the longer glume and lemma are the same length as the spikelet. The blooming period of the vernal form occurs from late spring to early summer and lasts about 1 week. The florets are cross-pollinated by the wind. Afterwards, the autumnal form of this grass develops an abundance of low lateral branches that are leafy and resemble a rosette. The autumnal blades of this grass are a little smaller in size than its vernal blades. Sometimes the lateral branches develop small panicles of florets that have fewer spikelets than the vernal panicle. The mature grains of the spikelets are about 2 mm. long, 1 mm. across, ovoid or broadly ellipsoid, slightly compressed, light tan, and hairless. The root system consists of a shallow knotty crown of fibrous roots.


Creative Commons Attribution Non Commercial 3.0 (CC BY-NC 3.0)

© John Hilty

Source: Illinois Wildflowers

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