TRIANDRIA MONOGYNIA. 303 



22. MARISCUS. 



M. rctrofractus : umbel simple ; rays long ; spikes obovate, retrorsely 

 imbricate ; spikelets sublunate, at length bent backward ; involii- 

 crum 3-leaved. 



HAB. Wet meadows. Aug. Sept. 1\.. Culm nearly naked, pubes- 

 cent ; umb. 6 8 rayed. 



23. DULICHIUM. 



D. spathaceum : culm terete ; leaves spreading in 3 directions ; spikelets 



spreading. 



HAB. Wet places. Aug. Sept. 7j. Culm very leafy, terete be- 

 low ; achrecR cylind. ; racemes axillary. 



24. CYPERUS. Cyprus-grass. 



C. inflexus : umbel 2 3 rayed, or conglomerate and simple ; involucrum 

 3-leaved, very long ; spikelets collected into ovate heads, oblong, 8- 

 flowered ; glumes squarrose at the tip. 



HAB. Banks of rivers. Aug. Sept. $1 2 -3 inches high '; odor- 

 ous ; heads many-Jl. ; glum, striate, yellowish. 



C. Jlavescens : spikes linear-lanceolate, in fascicles of 3 4 ; glumes ob- 

 tuse ; style 2-cleft; seed lenticular; involucrum 3-leaved, longer 

 than the spikes. 



HAB. Boggy grounds. Aug. Sept. *2J.. A span high ; spikelets 14 

 20-^., yellowish. 



C. Nuttallii: culm acutely triangular ; umbel radiate, or nearly sessile, 

 loose ; rays short ; involucrum 4-leaved ; 2 of the leaves very long ; 

 spikelets linear-lanceolate, compressed, acute ; stamens 2 ; style 2- 

 cleft ; seed oblong, obtuse, compressed. 



HAB. Borders of salt marshes. Aug. Sept. 7|. ; cespitose, 5 12 

 in. high ; spik. very acute ; glum, green and brown ; seed smooth. 



C. diandrus : culm slender, obtusely triangular ; umbel sessile, or 1 2- 

 rayed ; involucrum 3-leaved ; 2 of the leaves much longer than the 

 umbel ; spikelets lanceolate-oblong, much compressed, many-flower- 

 ed (14 16 ;) glumes margined, rather acute, keeled ; stamens 2 ; 

 style 2-cleft ; seed oval, compressed. 



HAB. Salt marshes. Sept. Tj. ; culm weak, not cespitose ; glume 

 much compressed, with a brown margin. 



O. dentatus: umbel compound, (6 10 rayed ;) involucrum 3-leaved, lon- 

 ger than the umbel ; spikelets 3 on each ray, alternate, ovate, com- 

 pressed, 8-flowered ; glumes acute, nervose, spreading at the points ; 

 seed triquetrous. 



HAB. Banks of rivers and sandy swamps. Sept. Tj. ; root tub. ; spik 

 appearing dentate, brownish ; sometimes viviparous. 



25. ERIOPHORUM. Cotton-grass. 



* Spike solitary. 



E. vaginatum: culm terete below, obtusely triangular above, smootn 



and rigid ; sheaths inflated ; spike oblong-ovate ; glumes scarious ; 

 wool straight, dense. 



HAB. Sphagnous swamps. July. 1\. ; cespitose, afoot high ; leaver 

 numerous ; glumes livid ; wool white. 

 27 



