'GENUS I/. 



GRASS FAMILY. 



ii. Panicum amarulum Ilitchc. & Chase. South- 

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



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



15: 96. 1910. 



Smooth and glabrous, glaucous, the tufted culms ii-4i 

 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, \-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 il" 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. 

 Aer. Agrost. 29: 5. 1901. 



Glaucous and glabrous. Culms scattered, i* -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 

 appressed; spikelets 2! "-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. Wild Red-top. Fig. 323 



Panicum I'irgatum L. Sp. PI. 59. i"53- 



/'. virgatum var. cnbense Griseb. Cat. PI. Cub. 233. 1866. 



Panicum rirgatum var. obtiisum Wood, Am. Bot. & Fl. 



392. 1870. 

 Panicum rirgatnin var. brci'iramosum Xash, 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 brandies 

 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, 

 5-7-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. 



