Switchgrass

Panicum ichnanthoides Fourn. Mex. PL Gram. 30. 1886
Panicum Buchingeri Fourn. Mex. PI. Gram. 30. 1886.
Plants in large clumps with knotted crowns, without creeping rootstocks; culms 1.5-2 m. high, erect or decumbent at the base, smooth, firm and hard, more or less glaucous about the nodes; leaf-sheaths shorter than the internodes, pubescent on the overlapping margin toward the apex, otherwise glabrous; ligule about 3 mm. long, membranaceous-ciliate ; blades elongate, mostly 8-15 mm. wide, flat except at the narrowed and usually inrolled base, scabrous on the margins, villous on the upper surface near the base, otherwise glabrous; panicles 20-40 cm. long, one fourth to one third as wide, the long slender branches ascending; spikelets 3.5-4.2 mm. long, about 1.5 mm. wide, similar to those of P. virgatum.
Type locality: Orizaba, Vera Cruz. Distribution : Southern Mexico to Nicaragua.

Panicum virgatum L. Sp. PI. 59. 1753
Panicum coloratum Walt. Fl. Car. 73. 1788. Not P. coloratum L/. 1767.
Eatonia purpurascens Raf. Jour.de Phys. 89: 104. 1819.
Panicum pruinosum Bernh.; Trin. Gram. Pan. 191, as synonym. 1826.
Panicum giganteum Scheele, L/innaea 22: 340. 1849.
Panicum glaberrimum Steud. Syn. Gram, 94. 1854.
Ichnanthus glaber Link; Steud. Syn. Gram. 94, as synonym. 1854.
Panicum Kunthii Fourn.; Hemsl. Biol. Centr. Am. Bot. 3: 490. 1885. Not P. Kunthii Steud.
1841. Panicum virgatum confertum Vasey, Bull. Torrey Club 13: 26. 1886. Panicum virgatum elongatum Vasey, Bull. Torrey Club 13: 26. 1886. Panicum virgatum diffusum Vasey, Bull. Torrey Club 13: 26. 1886. Chasea virgata Nieuwl. Am. Midi. Nat. 2: 64. 1911. Milium virgatum IyUnell, Am. Midi. Nat. 4: 212. 1915.
Plants erect, usually 1-2 meters high, producing numerous scaly, creeping rootstocks, glabrous throughout except as noted, commonly purple-tinged, often glaucous, especially on the internodes and upper surface of the blades; culms in large to small clumps or even solitary, 227
simple, robust, tough, and hard; leaf -sheaths longer than the rather short lower internodes, usually shorter than the upper ones, often ciliate, sometimes villous at the throat; ligule dense, 2-4 mm. long; blades ascending, 10-60 cm. long, 3-15 mm. wide, slightly narrowed toward the base, and gradually long-acuminate, flat, sometimes pilose on the upper surface toward the base, rarely to the apex, the margins scabrous; panicles long-exserted, 15-50 cm. long, mostly one third to half as wide, but sometimes contracted, or very loose and nearly as wide as long, usually many-flowered, the slender, scabrous, usually fascicled branches ascending or spreading, naked at base, repeatedly branching along the upper half or two thirds; spikelets rather short-pediceled, 3.5-5 mm., rarely but 3 or as much as 6 mm. long, 1.2-1.5 mm. wide, elliptic-ovate, acuminate, strongly nerved; first glume clasping, two thirds to three fourths the length of the spikelet, rarely equaling the sterile lemma, acuminate to cuspidate, 5-nerved; second glume longer than the sterile lemma, both much exceeding the fruit, 5-7-nerved; fruit narrowly ovate, the margins of the lemma inr oiled only at base.
Type locality: Virginia.
Distribution: Maine to Montana, south to Florida and Arizona, and through Mexico to northern South America.