68 CYPERACEAE. 



spreading, oval to elliptical, glabrous below, faintly nerved, the beak promi- 

 nent, scabrous, bifid or bidentate ; stigmata 3. 



Spikes androgynous, light-green. 65. C. Backii. 



Spikes staminate or pistillate on the same culm. 



Spikes green ; perigynium inflated, orbicular, the beak very long, linear, with 

 the orifice obliquely cut. 66. C. longirostris. 



Spikes shining, reddish-brown ; perigynium elliptical, the beak entire. 



67. C. capillaris. 

 24. SPIROSTACHYAE. 



Spikes several, rather short, dense-flowered, peduncled, but erect, remote, 

 squarrose at maturity, the terminal staminate, the lateral pistillate ; bracts 

 foliaceous, sheathing; scales light-brown, acuminate; perigynia greenish, 

 spreading, oval to elliptical, turgid, sessile, nerved, glabrous, the beak long, 

 scabrous, bifid ; stigmata 3. 



One species. 68. C. viridula. 



25. ECHINOSTACHYAE. 



Spike one, androgynous, or several, the terminal staminate, the lateral 

 pistillate, cylindrical, dense-flowered, peduncled, but erect, squarrose at ma- 

 turity; bracts foliaceous, very long, sheathing; scale? lanceolate, light-brown; 

 perigynium greenish, more or less inflated, nerved, glabrous, the beak long, 

 bidentate ; stigmata 3. 



Spike one, androgynous ; perigynium reflexed at maturity, narrowly lanceolate, 

 orifice of beak oblique ; rhacheola extended through orifice of the beak. 



69. C. microglochin. 



Spikes several, the terminal staminate, the lateral pistillate ; perigynium ovate, 

 much inflated, spreading at maturity, the beak bifurcate ; rhacheola not ex- 

 tended. 70. C. retrorsa. 



26. PHYSOCARPAE. 



Spike one, androgynous, or several, the terminal and, sometimes, the upper- 

 most lateral staminate, the others pistillate, cylindrical, sessile or the lower- 

 most peduncled, dark-colored ; bracts foliaceous, sheathless ; scales lanceo- 

 late, acuminate, brownish or purple; perigynia shining, spreading, but not 

 reflexed, membranaceous, globular to oblong-elliptical, inflated, sessile; 

 nerved, the beak short, bidentate or merely emarginate ; stigmata 2 or 3. 



Spike single, androgynous ; perigynium elliptical, tapering into a bidentate beak. 



71. C. Engelmannii. 

 Spikes several. 



Pistillate spikes cylindrical, often very long ; perigynium inflated, many-nerved, 

 oblong-elliptical, tapering into a cylindrical, bifurcate beak ; stigmata 3. 



72. C. utriculata. 

 Pistillate spikes short, blackish ; perigynium slightly inflated, broadly ovate, 



nerveless, the beak short, emarginate ; stigmata 2. 73. C. pnlla. 



27. RHYNCHOPHORAE. 



Spikes several, cylindrical, very robust and dense-flowered, sessile or nearly 

 so, mostly erect, contiguous, the terminal and, sometimes, the uppermost 

 lateral staminate, the others pistillate ; bracts foliaceous and very long, sheath- 



