GRAMHSTE.E. (GRASS FAMILY.) 591 



2. R. COrrugata, Baldw. Culm stout, compressed ; peduncles mostly 

 single ; spikes slightly compressed, erect ; lower glume longitudinally grooved 

 and somewhat reticulated, ovate ; sterile flower staminate. Low pine barrens, 

 Georgia and Fli >rida, near the coast. Sept. - Oct. Culm 2 - 4 high. Spikes 

 4' - 6' long, 2" in diameter, purplish. 



3. R. cylindrica, Chapm. Culm slender, terete ; leaves narrowly lin- 

 ear; peduncles single, elongated ; spikes slender, terete, mostly curved ; spike- 

 lets as long as the joint ; lower glume ovate, obtuse, obscurely pitted in lines ; 

 sterile spikelet rudimentary. Dry sandy soil, Florida, and westward. July - 

 Sept. Culms 1- 2 high. Spikes 2' - 6' long, 1" iu diameter, purplish. 



18. MANISURIS, L. 



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

 Spikes lateral and terminal, jointed, the short peduncles enclosed in spathe- 

 like sheaths. Spikelets 1 -flowered, placed one at each end of the joints of the 

 spike ; the upper neutral, compressed, of two nearly equal membranaceous 

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

 reticulated. Palet hyaline. Stamens 3. Grain included. 



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

 sheaths, hairy ; spikes 6" - 10" long ; spikelets minute, turning black. Fields 

 and pastures. August -Sept. Introduced. Culms 1- 2 high. 



19. TRIPSACUM, L. GAMA GRASS. 





 Tall perennial grasses, with solid culms, broad and flat leaves, and spiked 



inflorescence. Spikes jointed. Spikelets 2-flowered, the upper ones staminate, 

 the lower fertile, 2-flowered. Stamiuate flowers by pairs on each short trian- 

 gular joint of the slender rachis, 3-androus ; glumes 2, coriaceous ; paleae hya- 

 line. Pistillate spikelets single, embedded in a deep excavation of the thick 

 and polished joints ; the outer glume cartilaginous, concave, the inner mern- 

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

 hyaline paleai. Anthers opening by terminal pores. Stigmas elongated. 

 Grain free. 



1. T. dactyloides, L. Culms erect, 3 -6 high; leaves 2 -3 long, 

 1' wide; spikes 1 -3, 4' -8' long, on long lateral and terminal peduncles, the 

 fertile joints 3-5, angular, or, in var. monostachyum, several and terete. 

 Dry rich soil, common. 



2. T. Floridanum, Porter. Culms more slender, 2 - 4 high ; leaves 

 narrower and more rigid ; spikes single, 6' - 1 0' long, erect ; the joints shorter ; 

 spikelets smaller, 2-ranked. Florida, and westward. 



20. ELIONTTRUS, HBK. 



Tall erect perennial grasses, with the inflorescence of Andropogon, but the 

 awnless spikelets borne alternately on two sides of the slender flexuous rachis, 

 forming a solitary long-peduncled villous spike. 



1. E. tripsacoides, HBK. Culms (3 -4 high) straight, smooth like 

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

 sterile flower fringed with closely appressed white hairs ; spikelets awuless ; 



