CYPERACE^E. (.SEDGE FAMILY.) 537 



high), rough-angled above ; leaves broad, elongated, reticulated. Miry places, 

 Florida to North Carolina. July -Sept. 2/ Plant pale green. Rays 3'- 

 4' long. Spikelets turning yellowish. 



26. C. calcaratus, Nees. Umbel often decompound, many-rayed, widely 

 spreading ; involucre 4-leaved, many times longer than the umbel ; spikelets 

 short (1-J-" -2" long), ovate, 10- 15-flowered, very numerous in the heads; 

 scales lanceolate, incurved, spreading at the apex ; nut minute, linear-lanceo- 

 late, slender-pointed; culms slender (2 -3 high), obtuse-angled or nearly 

 terete ; leaves narrow, rigid, rough on the margins near the summit. Low 

 pine barrens and margins of ponds, Florida to North Carolina. Sept. 2/ 

 Culms tumid at the base. Leaves of the involucre horizontal. Heads light 

 brown. 



27. C. Surinamensis, Rottb. Umbel compound, of 4-6 primary rays, 

 and as many smaller ones, shorter than the 4-leaved involucre ; spikelets (10- 

 20 in a cluster) oblong or oblong-linear, 40 - 50-flowered ; scales yellowish, 

 ovate, straight, free at the apex ; nut oblong, pointed, abruptly contracted at 

 the base, minutely wrinkled; culms (6' -15' high) obtuse-angled, very rough, 

 longer than the narrow leaves. Sandy swamps, Middle Florida, and west- 

 ward. Sept. (T). 



* * Umbel simple or sessile : spikelets lanceolate or linear, compressed : scales 

 8 - 10-nerved, tapering into a long spreading or recurved point: nut obouate- 

 oblong : low tufted annuals. 



28. C. aristatUS, Kottb. Umbel of 1-2 short rays or sessile, much 

 shorter than the 2 - 3-leaved involucre; spikelets very numerous in the clus- 

 ters (green), oblong-linear (2" long), 10 -20-flowered ; scales thin, oblong, 8- 

 nerved, gradually pointed ; culms weak, acute-angled (2' -6' high), as long as 

 the smooth narrowly linear leaves. Low sandy places (apparently intro- 

 duced). July - Sept. Sheaths of the leaves green. 



Var. versicolor, Clarke. Spikelets 8-20 in a cluster, reddish brown; 

 scales rigid, 10-nerved, abruptly pointed; sheaths dark brown. South 

 Fl< >rida. 



29. C. acuminatus, Torr. Spikelets (whitish) numerous in a compact 

 cluster, oblong, compressed, 20-30-flowered ; scales thin, keeled, oblong, 

 tapering into a spreading point, faintly 3-nerved ; nut minute, narrowly obo- 

 vate ; culms clustered ; leaves one or two, very narrow, like the 3-leaved in- 

 volucre. Low ground, Tennessee, and westward. Culms 4' -8' high. 



5. Umbel simple or sessile : spikelets inserted on all sides of the common rachis, 

 forming clusters or heads : joints of the rachis mostly winged : scales rigid, 

 5-ll-nen-ed: stamens 3. 



* Spikelets few in loose clusters. 



30. C. filiformis, Swartz. Clusters sessile ; spikelets 6-12, erect, terete, 

 subulate, 6 - 12-flowered ; scales scattered, appressed, oblong, mucronate, finely 

 nerved; rachis verv slender, flexuous ; nut oblong, acute ; culms tufted, fili- 

 form, acute-angled, longer than the bristle-like leaves; involucre 2-leaved. the 

 lower one elongated and erect. Key West. Nov. ^ Culms 4' -10" 

 high, tumid at the base. Spikelets 4" - 6" long. 



