IUCN threat status:

Not evaluated

Comprehensive Description

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This grass is a short-lived cool-season perennial. From fall to early spring, it consists of a tuft of sprawling basal leaves less than 6" tall. From mid-spring to early summer, leafy culms develop that are 6-20" long; these culms are erect to sprawling. The slender culms are light to medium green, terete, hollow, glabrous, and unbranched. Alternate leaves occur primarily along the lower one-third of each culm. The linear leaf blades are 1-3 mm. across and 1-4" long; they are medium green to grayish blue, glabrous, and either flat or furrowed in the middle; their tips are hull-shaped. The leaf sheaths are medium green, longitudinally veined, glabrous, and rather loose; the upper two-thirds of each sheath are open, while the lower one-third is closed. The nodes are slightly swollen and dark-colored, while the ligules are white-membranous. Each culm terminates in an ovoid to oblongoid panicle of spikelets or aerial bulblets. The typical panicle is 1½-4" long and 1-1½" across; it has a slender central stalk (rachis) and whorls of 2-3 wiry lateral branches that are more or less horizontal below and ascending above. The lateral branches often divide into secondary branches that terminate in either flattened spikelets or clusters of scaly bulblets; both spikelets and bulblet clusters have short pedicels. Individual culms can produce all spikelets, all bulblets, or a mixture of the two. In Illinois, most culms produce only bulblets. When spikelets are produced, they are 4-6 mm. long, consisting of a pair of glumes at the bottom and 2-6 lemmas above that have perfect florets. The glumes and lemmas are arranged into two ranks that are columnar and overlapping. The narrow glumes and lemmas are keeled; the glumes are 2-3.5 mm. long, while the lemmas are 2.5-3.5 mm. long. In each spikelet, one glume is a little longer than the other. Each lemma has a midvein along the keel and 2 marginal veins that are minutely pubescent, at least along the lower half of each vein (requires 10x magnification to see). Individual florets have 3 stamens and a pair of feathery stigmata. The aerial bulblets are about 1/4" long and 1/8" across; they have purple bases and greenish purple or greenish white scales (modified lemmas). At the apex of each bulblet, one or more aerial basal leaves are produced that are green and narrowly linear in shape; they are up to 1" long. Each cluster of aerial bulblets has a pair of glumes underneath that are lanceolate and slightly succulent. When spikelets are produced, the blooming period occurs during late spring or early summer. The florets are wind-pollinated. In Illinois and other areas of North America, relatively few spikelets produce grains. Aerial bulblets also develop during the late spring and early summer; they become mature later in the summer, becoming detached from the mother plant. By forming rootlets in the ground, the bulblets are capable of forming clonal plants. The root system of a plant consists of a terrestrial bulb with secondary fibrous roots below. New bulbs are often produced below ground as vegetative offsets.


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

© John Hilty

Source: Illinois Wildflowers


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