580 GRAMINE.E. (GRASS FAMILY.) 



the joint ; lower glume ovate, obtuse, obscurely pitted in lines ; sterile spikelet 

 rudimentary. (Tripsacum cylindricnm, Michx.) — Dry sandy soil, Florida. 

 July - Sept. — Culms 1° - 2° high. Spikes 2' -6' long, 1 " in diameter, purplish. 



54. MANISURIS, L. 



Annual grasses, with branching culms, flat leaves, and spiked inflorescence. 

 Spikes lateral and terminal, clustered, jointed, the short peduncles enclosed in 

 Bpathe-like sheaths. Spikelets L-flowered, placed one at each end of the joints 

 of the spike ; the upper neutral, compressed, of two nearly equal hispid mem- 

 branaceous glumes ; the lower perfect, globose. Glumes coriaceous, concave, 

 the lower reticulated, the upper smooth. Palerc 2, hyaline. Stamens 3. Grain 

 included. 



1 . M. granularis, Swarte. Leaves linear-lanceolate, and, like the sheaths, 

 hairy; spikes 0" - 10" long ; spikelets minute, turning black. — Fields and pas- 

 tures, Florida to South Carolina. Aug. and Sept. Introduced. — Culms l°- 

 2° high. 



55. TRIPSACUM, L. Gama-Grass. 



A tall perennial grass, with solid culms, broad and flat leaves, and spiked 

 inflorescence. Spikelets awnless, monoecious, in jointed spikes, the upper ones 

 Btaminate, the lower fertile, 2-flowered. Staminate flowers by pairs on each 

 short triangular joint of the slender rachis, 3-androus ; glumes 2, coriaceous; 

 pales hyaline. Pistillate spikelets single, embedded in a deep excavation of 

 the thick and polished joints; the outer glume cartilaginous, concave, the inner 

 membranaceous, boat-shaped; lower flower neutral, the upper pistillate, both 

 with hyaline paleas. Anthers opening by terminal pores. Stigmas elongated. 

 Grain free. 



1. T. dactyloides, L. — Rich soil, Florida, and northward. Aug. and 

 Sept. — Culms erect, from tufted creeping rootstocks, 3° -5° high. Leaves 1' 

 wide. Spikes 4' -8' long, on long lateral and terminal peduncles, 2-4 in a 

 cluster or sometimes solitary. (T. monostaehyum, Willd.) 



56. ANDROPOGON, L. Broom-Grass. 



Coarse perennial grasses, with branching erect culms, long and harsh leaves, 

 and spiked inflorescence. Spikes lateral and terminal, jointed. Spikelets by 

 pairs on each joint of the slender commonly hairy or plumose rachis; one of 

 them pedicelled and staminate, neutral, or rudimentary ; the Other sessile, 2- 

 flowered, the lower flower consisting of one palea, and neutral ; the upper of 

 2 palea?, mostly perfect, shorter than the herbaceous or chartaceous glumes, the 

 lower one mostly awnod at the apex (except No. 1 ). Stamens 1 - 3. Grain free. 



§ 1. ANDROPOGON Proper. — Upper flower perfect. 

 * Peduncle solitary, bearing <i single spike. 

 l. A. Nuttallii. Culms (3° -4° high) Btraight, Bmooth, like the long 

 linear leaves ; spikes rigid, long-peduncled, the rachis and pedicel of the sterile 



