MONOCOTYLEDOKOUS OR ENDOGENOUS PLANTS. 613 



upper one ; stamens 3 ; grain included in the indurated 

 puleae. Such is the apparent structure of the spikelet, but 

 theoretically it is 2-flowered, as in Panicum, with the lower 

 glume and upper palea of the lower flower undeveloped. 



* Spikes racemed ; spikelets partly inclosed by the recurved margins of the broadly- 

 winged membranaceous rachis. 



P. Walteri, Schultes. Smooth ; spikes 3-7, the lowest 

 ones included in the sheath of the uppermost leaf; spikelets 

 in two rows, ovate, smooth ; glumes obtuse, 5-nerved. (P. 

 vaginatum. Ell.) July and August. Culms decumbent, 

 creeping, 1^-3° long; leaves linear, short. 



** Spikes mostly by pairs, divaricate ; spikelets ovate-lanceolate, acute, 2-rowed on the 

 slender wingless rachis ; glumes smooth, longer than thepaJ.eoe. 



P. VAGINATUM, Swartz. Peduncles single, terminal, 

 spikes (rarely 3 or 4) short (I'-IJ-' long), erect or hori- 

 zontal; glumes rugose, 5-nerved, rather longer than the 

 acute flow^er; culms diffusely creeping, short-jointed, the 

 flowering branches (4-10' long) erect; leaves (l'-3' long) 

 subulate-convolute, their dilated imbricated sheatlis per- 

 sistent. (P. furcatum, Fluegge.) Saline swamps. August 

 and September. Culms 2°-4° long; sheaths compressed, 

 bearded at the throat. Perennial. 



*** Spikes soWary, or few and racemose ; spikelets ovate or roundish, in 2-4 rows; 

 rachis mostly flattened and flexuom ; glumes andpalece nearly equal. 



P. L^VE, Michx. Spikes 3-5, long (3-4') and slender; 

 spikelets single, in 2 rows, orbicular, wider than the flexu- 

 ous rachis; glumes smooth and even, 5-nerved; ctilms 

 simple, erect (3°-4° high) ; leaves (deep green) and sheaths 

 smooth, or the latter liairy. Dry w^oods. July and August. 

 Spikelets 11" long, larger and thicker than the last. Per- 

 ennial. 



P. UNDULATU^r, Poir. Spikes 2-12, spreading (2'-3' 

 long) ; spikelets small (1" long), oval or roundish, crowded 

 in 3-4 rows under the broad and flat rachis ; glumes smooth, 



