340 ENDOGENOUS PLANTS 



** Culm terete. 



3. S. lacustrl, L. Culm large, tapering above, even and 

 smooth ; spikelets numerous, cymose-panioled. 



LAKE SCIRPUS. Bull-rush. 



Culms 4 to 6 or 8 feet high, naked, glaucous, terminating in a cusp of 1 to 2 

 inches in length above the panicle ; sheatfis at base bearing short leaves. SpikeUts 

 often clustered in threes at the ends of the branches, with one or more sessile, in 

 the centre ; scales brown, slightly pubescent, the margins ciliate. Akene pal^ 

 greenish-white, mucronate; bristles usually 4, retrorsely hispid, a little longer 

 than the akene. 

 JBdb. Margins of ponds, and ditches : frequent. Fl. June. Fr. Aug. 



4. S. debills, Pursh. Culm slender, deeply striate; spikelets 

 few, in a sessile cluster. 



WEAK SCIRPUS. 



Culms 9 to 18 inches high, naked, glabrous, loosely sheathed at base. Spikelets 

 1 to 6 or 8 generally 3 turgid, in a lateral cluster 2 or 3 inches from the summit 

 of the culm; scales pale green, membranous. Alcene black, shining, punctate, 

 mucronate ; bristles 6, retrorsely hispid, a little longer than the akene. 

 Hob. Wet, sandy low grounds : frequent. Fl. Aug, Fr. Sept. 

 c. Spikelets numerous, manifestly terminal, in a decompound cymose umbel: culm 

 obviously nodose and leafy, rigid, triangular; style trifid, and akene trigon- 

 ous ; bristles retrorsely pubescent. 



5. S. atrovirens, Muhl. Spikelets densely clustered in heads 

 of 8 or 10 to 20, dark green; bristles the length of the akene. 

 DARK-GREEN SCIRPUS. 



Culms 2 to 4 or 5 feet high. Leaves broadly linear, shorter than the culm. 

 Involucre foliaceous, usually of 3 leaves, longer than the cymose umbel. Heads 

 of spikelets roundish-ovoid ; scales acute, with a distinct point, finally becoming 

 brownish. Akene whitish, smooth, mucronate; bristles usually 4 or 5, sometimes 



6. nearly straight, not hispid, but with a minute retrorse pubescence. 

 Hab. Swamps, and wet meadows : frequent. Fl. July. Fr. Aug. 



Obs. The spikelets range from 8 to 20, or more, in a head, and 

 are sometimes viviparous. % 



6. S. polyphyl'llis, Vahl Spikelets clustered in heads of 3 to 

 C or 8, yellowish-brown ; bristles twice the length of the akene. 

 S. brunneus. Muhl. $ Fl. Cestr. ed. 2. p. 22. 

 MANY-LEAVED SCIRPUS. 



Culms 2 to 4 feet high, obtusely triangular. Leaves rather numerous, loosely 

 sheathing, broadish, longer than the culm. Involucre of 4 or 5 leaves. Spikeltts 

 rather larger than in the preceding species, commonly in clusters of 3 to 6, some- 

 times more ; scales rather obtuse, but slightly mucronate, at first yellowish-green, 

 finally reddish-brown. Akene yellowish, smooth, short-beaked ; bristles 4 to 6 3 a 

 little tortuous, or crisped, minutely and retrorsely hispidulous. 

 Hub. Wet, low grounds ; thickets, Ac. : rather frequent. Fl. July. Fr. Aug. 



g 2. TRICHO'PHORUM : Perigynium of soft, smooth, tortuous or crisped hairs ; culm 

 nodose and leafy ; style trifid, and akene trigonous. 



7. S. lineatllS, MX. Spikelets cylindric-oblong, solitary and 

 pendulous on the long filiform peduncles ; involucre of 1 to 3 short 

 leaves ; hairs a little longer than the scales. 

 LINED SCIRPUS. 



