odor at a Vahl. 



Frequent in moist sandy loam, and on seepage slopes in e. Tex. (Angelina, 

 Austin, Gonzales, Hardin, Lavaca and Newton cos.), June-Oct.; widespread in 

 warm regions. 



5. Cyperus albomarglnatiis Mart. & Schrad. Fig. 216. 



Tufted annual; culms 2-9 dm. long, basally leafy and 2-8 mm. thick, apically 

 0.7-4 mm. thick; inflorescences 2-13 cm. long, of 3 to 12 very unequal peduncles 

 each bearing a lax spike 12-40 mm. long and 12-23 mm. thick, of 10 to 60 

 spreading spikelets or the longer peduncles bearing secondary peduncles with 

 such spikes; bracts 3 to 7, far-surpassing the inflorescence; spikelets 5-12 mm. 

 long, 1.7-3 mm. broad, about 0.7 mm. thick, with 6 to 18 scales, straw-brown to 

 dark-chocolate-brown, straight, the axis somewhat 4-angled, at maturity persistent, 

 each internode on the fertile side with a niche for an edge of the achene and on 

 the edges (at the sides of the achene) with minute winglike margins; scales 1.4- 

 1.7 mm. long, 1.4-2 mm. broad, obovate, membranous, with 5 nerves at the keel- 

 like median and marginally with a broad hyaline zone (albomargin) markedly 

 contrasting with the brownish sides, deciduous, not much overlapping, clasping 

 the achene; stamens 2 or 3; achenes lenticular, with an angle fitting into the niche 

 of the internode, nearly as long as the scale, broadly obovate, apiculate, 1.2-1.5 

 mm. long, 0.6-1 mm. broad, maturing to black. 



Infrequent or rare, on rocky slopes, washes and along streams, scattered in 

 s.e. and Trans-Pecos Tex. and Ariz. (Cochise, Pima and Santa Cruz cos.), sum- 

 mer; Afr., Madag., India, Burma, Austral.; in Am. from Arg. and Bol. n. to Va., 

 N.C., S.C, Ala., La., Tex. and Ariz. 



6. Cyperus polystachyos Rottb. var. texensis (Torr.) Fern. Fig. 217. 



Tufted perennial (flowering the first year); culms 3-35 cm. long, basally 0.8-3 

 mm. thick, apically 0.5-1.5 mm. thick, wiry; leaves basal, mostly shorter than the 

 culms; inflorescence 12-60 mm. long, of several unequal peduncles (these, es- 

 pecially in coastal populations, suppressed so that inflorescence is congested) with 

 glomerules or short lax spikes, or rarely the longer ones with secondary peduncles 

 1-3 mm. long each with a glomerule or lax spike; glomerules or lax spikes with 

 5 to 10 mostly spreading spikelets; bracts 1 to 6, the longer ones usually about 

 twice as long as the inflorescence; spikelets 4-25 (-43) mm. long. 0.7-2 mm. 

 broad, about 0.5 mm. thick, with 10 to 40 (to 60) scales, brownish-buff to tawny- 

 stramineous, straight, the axis slightly 4-angled, at maturity persistent, each inter- 

 node on its fertile side with a niche for one edge of the achene, near the base of 

 the niche with minute hyaline wings that narrow and join abaxially forming a 

 minute cup at the base of the achene (use a strong lens!); scales 1.4-2 mm. long, 

 about 1 mm. broad, ovate, appressed, much-overlapping, with 3 obscure nerves at 

 the keel-like median, deciduous; stamens 2; achene lenticular, with an angle fitting 

 the niche of the internode, about 1 mm. long, oblong to narrowly oblong, ripen- 

 ing through brown to black. Incl. var. leptostnchyus Boeck. 



Locally abundant in seasonally moist sand, in muddy shallows, on vegetation 

 mats in lakes, and at edge of stream, in Okla. (McCurtain and Johnston cos.), 

 e. and s.e. Tex. and coastal part of Rio Grande Plains, spring-fall; widespread 

 in Am. n. to Mass., Pa., Mo., Ark., Okla. and Tex.; the var. polystachyos (C. 

 filicinus Vahl) occurs in coastal areas, Mass. to Va.; the var. paniculatus (C. 

 vulgaris var. teretifructus (Steud.) Miq.) occurs widely in trop. of both hemi- 

 spheres. 



7. Cyperus flavescens L. Fig. 216. 



Tufted annual; culms 10-25 cm. long, basally 0.8-1.9 mm. thick, apically 

 0.7-1.1 mm. thick; inflorescence a congested (compound) sessile head of 10 to 35 



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