M0N0C0TYhEJ30X0US OR ENDOGENOUS PLANTS. 5T3 



§ 1. PrcREUs. style '2-cleft ; nut lenticular ; spikes more or less umbelled. Annuals; 

 spilcetcts linear or linear-oblong, Jlat, many- (10-40) -flowered; rachis narrowly 

 margined ; scales compressed-keeled, 5-nerved. 



* Spikelets clustered on the common rachis. 



C. FLAVESCENS, L. Umbel sessile or of 2-4 rays, shorter 

 than the spikelets ; spikelets 3-several in a cluster, oblong- 

 linear, acute, spreading, 20-30-flowered ; scales yellowish 

 brown, ovate,- obtuse, appressed ; rachis margined; sta- 

 mens 3 ; 7i2it orbicular, black, smooth and shining; cidmo 

 clustered, 4-10' high ; leaves and 3-leaved involucre nar- 

 rowly linear. (0. fasciculatus, Ell. ?) 



G. DIANDRUS, Torr. Umbel of 2-5 short and unequal 

 rays, the longer ones longer than the spikelets; sjnkelets 

 lanceolate-oblong, acute, brownish or dark brown, spread- 

 ing ; scales ovate, obtuse, appressed, green on the keel ; 

 rachis margined ; stamens 2 ; mit oblung-obovate, ruugh- 

 ish, dull gray. Wet places. August. Culms 4:' -10' high; 

 involucre 3-leaved. This and tne preceding are probably 

 only diandrous forms of C. flavescens. 



** spikelets scattered on the common rachis {spiked.) 



C. FLAVICOMUS, Michx. Umbel' compound, many-rayed; 

 spikelets very numerous, crowded, linear, acute, 12-30- 

 flowered ; scales loosely imbricated, yellowish, round-obo- 

 vate, emarginate, with broad and scarious margins, at 

 length spreading; rachis broadly margined; stamens 3; 

 nut obovate, black, smooth and shining, bar.dy shorter 

 than the scale; culms thick, obtuse angled ; l°-3° high ; 

 leaves broadly linear, glaucous beneath, as long as the culm. 

 Low grounds and ditches. May-September. Involucre 

 3-5-leaved ; spikelets 6"-9" long. 



C. MiCRODON-Tus, Torr. Umbel of 4-8 rays, simple or 

 somewhat compound ; spikelets numerous, crowded, linear, 

 acute, 15-25-flowered, pale brown ; scales thin, ovate, 

 acute, closely imbricated ; rarJiis slightly margined; sta- 

 mens 2 ; 7iut linear-oblong or somewhat club-shaped, short- 



