286 REPORT OF NEW JERSEY STATE MUSEUM. 



ee. Low tufted, pistillate spikes nearly sessile, staminate ele- 

 vated 25-50 mm., both far exceeded and concealed by the 

 old dry leaves, which persist in large numbers. 

 f. Perigynia puberulent. C. umbel lata, p. 304 



ff. Perigynia glabrous, or puberulent only on the angles 

 of the beak. C. u. tonsa, p. 304 



cc. Staminate spikes, several. 



d. Perigynia beak notched or toothed at tip. 

 e. Perigynia pubescent. 



/. Teeth at tip of perigynia, less than i mm. long. 



C. lanuginosa, p. 296 

 ff. Teeth at tip of perigynia more than i mm. long. 



C. trichocarpa, p. 294 

 ee. Perigynia glabrous. 



/. Pistillate spikes, 17 mm. thick, about twice as long as 

 thick, usually single, staminate spikes usually 2. 



C. bulla ta, p. 292 

 ff. Pistillate spikes, 10-12 mm. thick, about three times as 

 long as thick. 



g. Perigynia yellow straw color, much inflated at the 

 base, abruptly contracted into a slender beak. 

 h. Spongy at the base of the stem. 



C. utriculata, p. 292 

 Ilk. Base of stem not spong}". C. nionile, p. 292 



gg. Perigynia brownish, tapering gradually. 



/;. Staminate spikes 3-4, pistillate spikes 25-IOO 

 mm. long. C. lacustris, p. 294 



hh. Staminate spikes 2, pistillate spikes 10-50 mm. 

 long. C. zvalteriana, p. 295 



dd. Perigynia tapering into a hollow slender beak, obliquely trun- 

 cate at the tip, not notched. C. polymorpha, p. 301 

 ddd. Perignia plano-convex, not beaked, pistillate spikes very 

 slender, 3 mm. thick, with closely imbricated perigynia. 

 Swamp species forming dense tussocks. C. stncta, p. 296 

 bb. Staminate spike sessile or on a short peduncle, so that it does not 

 stand clear of the adjacent pistillate spike when the latter (or the 

 perigynia composing it) is brought close against the stem. Staminate 

 spike always single. 

 c. Achenes 7-12 mm. long. 



d. Spindle-shaped, tapering gradually. 



e. Spike i of only 3-6 achenes, spreading or reflexed. 



C. collinsii, p. 290 

 ee. Spikes about 4 of numerous achenes in fan-shaped clus- 

 ters, rather remote and not over 15 mm. long. 



C. folHculata, p. 291 



dd. Sharply triangular, abruptly narrowed to a long, very slender 



twisted beak, spikes 4-5, dense and cylindrical 40 mm. long. 



e. Achenes rhombic ovoid, the angles round knobbed in the 



middle. C. lupuliformis, p. 292 



