GENUS 17. 



GRASS FAMILY. 



141 



ii. Panicum amarulum Hitchc. & Chase. South- 

 ern Sea-beach Grass. Bitter Panic. Fig. 321. 



Panicum amarulum Hitchc. & Chase, Contr. U. S. Nat. Herb. 



15 : 96. 1910. 



Smooth and glabrous, glaucous, the tufted culms i2-4* 

 tall; sheaths overlapping; blades 6'-i long, 3"-6" wide, 

 long-acuminate, thick and leathery, involute on the margins, 

 at least toward the apex, the uppermost leaf exceeding the 

 panicle; panicle contracted, i-2 long, its branches erect; 

 spikelets about 2\" long; the first scale one-half to two- 

 thirds as long as the spikelet, the third somewhat longer 

 than the second, usually with a palet and staminate flower, 

 the fourth elliptic, about if" long. 



On sea-beaches, Virginia to Florida and Mississippi ; also 

 in the Bahamas, Cuba and Jamaica. Confused in our first edi- 

 tion with the following species. Sept.-Nov. 



12. Panicum amarum Ell. Smaller Sea- 

 beach Grass. Fig. 322. 



Panicum amarum Ell. Bot. S. C. & Ga. i: 121. 1817. 

 Panicum amarum var. minor Vasey & Scribn. Bull. U, 

 S. Dep. Agr. Bot. 8: 38. 1889. 



Panicum amaroides Scribn. & Merr. Circ. U. S. Dep. 

 AST. Agrost. 29: 5. 1901. 



Glaucous and glabrous. Culms scattered, i-2-3 

 tall, from a stout creeping rootstock ; leaves thick 

 and firm; sheaths overlapping; blades up to i long, 

 3"-5" wide, flat, or involute toward the apex ; panicle 

 6'-ii long, contracted, narrow, the short branches 



i appressed; spikelets 2-J"-3" long, commonly broad 

 and stout, the first scale more than i as long as the 

 spikelet to nearly equalling it, the second and third 



^ scales about equal, all acute. 



In sands along the coast. Connecticut and Long 

 Island to Florida and Mississippi. Aug.-Oct. 



13. Panicum virgatum L. 



Switch-grass. 



Panicum rirgatiim L. Sp. PL 59. 1753. 



P. I'irgatiim var. cubcnsc Griseb. Cat. PL Cub. 233. 1866. 



Panicum rirgatitm var. obtusum Wood, Am. Bot. & Fl. 



392. 1870. 

 Panicum rirgatum var. breviramosiim Nash, Bull. Torr. 



Club 23 : 150. 1896. 



Culms erect from a creeping rootstock, 3-6 tall, 

 glabrous. Sheaths smooth and glabrous; blades elon- 

 gated, i or more long, 3 "-6" wide, flat, long-acumi- 

 nate, narrowed toward the base, glabrous, rough on 

 the margins ; panicle 6'-2o' long, the lower branches 

 4'-io' long, rarely shorter, spreading or ascending; 

 spikelets ovate, acute to acuminate, \\"-2.\" long; first 

 scale acuminate, about one-half as long as the spikelet, 

 3-5-nerved ; second scale generally longer than the others, 

 5-/-nerved, the third similar and usually subtending a 

 palet and staminate flower; fourth scale shining, shorter 

 than the others. 



In moist or dry soil, Maine to the Saskatchewan, south 

 to Florida, Arizona and Costa Rica. Also in the West In- 

 dies. Thatch-grass, Wobsqua-grass, Black-bent. Aug.-Sept. 



Wild Red-top. Fig. 323. 



