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This perennial grass is about 2-3' tall and unbranched. Each culm is green, slender, glabrous, and terete in cross-section. The leaf blades are up to 8" long and 1/3" (8 mm.) across; they are green, bluish green, or grayish blue, linear in shape, hairless, and rather flat. The sheaths are green, glabrous, longitudinally veined, and open; they often split open at their apices, forming a deep V-shape. The nodes of the culm are red and glabrous, while the ligules are white-membranous. The culm terminates in a panicle of one-flowered spikelets. This panicle is up to 8" long and one-half as much across; when fully open, it is broader at the base than at the top and rather airy in appearance. Along the rachis (central stalk) of the panicle, there are whorls of ascending to widely spreading lateral branches; these branches are reddish green or pale red, glabrous, and straight. The spikelets and pedicels are held in alignment with the lateral branches. The short pedicels of the spikelets are reddish green or pale red and glabrous. Each spikelet is 2-3 mm. in length; it consists of 2 glumes about 2-3 mm. long, a single fertile lemma about 1.5-2 mm. long, an inner palea that is a little shorter than the lemma, and a perfect floret. The glumes are lanceolate in shape and keeled; there are often fine hairs or bristles along the edges of their keels, although this is difficult to see without magnification. The fertile lemma is greenish white to white, translucent, and lanceolate in shape; the inner palea is white-membranous. While the flowers are blooming, the spikelets are light silver-red. Shortly afterwards, the spikelets become light gray and rather dull. The blooming period usually occurs from late spring to mid-summer, lasting about 1-2 weeks for a colony of plants. The florets are cross-pollinated by the wind. At maturity, the spikelets disarticulate above the glumes. The grains are 1.0-1.5 mm. long, ellipsoid in shape, and light brown. The root system is fibrous, also producing rhizomes or low stolons. Redtop is a sod-forming grass that forms dense clonal colonies. This grass also readily reseeds itself.


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

© John Hilty

Source: Illinois Wildflowers

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