spikelets plus occasionally 1 to 3 peduncles 1-3 cm. long each with a head of 4 to 

 10 spikelets; bracts 1 to 4, the longer ones usually surpassing the inflorescence; 

 spikelets 6-20 mm. long, 1.8-3 mm. broad, about 0.8 mm. thick, with 22 to 40 

 scales, mostly straight, uniformly stramineous to ochre-stramineous, the axis per- 

 sistent straightish, flattened, essentially wingless, each internode with a niche into 

 which fits an angle of the achene; scales deciduous, 1.5-2 mm. long, 1.2-1.6 mm. 

 broad, ovate, with 3 nerves in the keel-like median; stamens normally 3; achene 

 lenticular (biconvex), about 0.9 mm. long and 0.6 mm. broad, obovate, sub- 

 stipitate, short-apiculate. ripening to black, surficially shiny and with rectangular 

 linear (vertical) cells (the rows of these cells marked off by horizontal wavy 

 usually discolored sutures). Incl. var. pooefonnis (Pursh) Fern. 



Infrequent or rare in moist or wet sand, wet meadows, ditches and on seepage 

 slopes, in Okla. (Waterfall), e., s.e. and n.-cen. Tex., July-Nov.; widespread (in 

 several varieties) in warm regions; in Am. n. to N.Y., Pa., Mich., Mo. and Kan. 



8. Cyperus niger R. & P. Fig. 218. 



Annual or usually weak perennial occasionally forming mats by rooting or very 

 shortly decumbent culms; aerial parts 1-4 (-6) dm. long, mostly erect, sub- 

 basally 1-2 mm. thick, apically 0.4-1.4 mm. thick; leaves few, mostly much 

 shorter than the culms; inflorescence commonly of a single sessile irregular head 

 1-2 cm. thick of 3 to 30 spikelets, rarely more elaborate with a sessile head plus 

 2 or 3 peduncles to 4 cm. long each with a lax irregular head or glomerule of up 

 to 20 spikelets; bracts 1 to 3, the longest far-surpassing the inflorescence and 

 (when young) commonly erect (like a continuation of the culm), later spreading; 

 spikelets 7-12 mm. long, 1.7-2.2 mm. broad, about 0.7 mm. thick, with 10 to 22 

 scales, straight, pale-chestnut-brown or often with darker blotches of chestnut on 

 each scale, rarely almost totally dark-brown, the axis persistent, somewhat 4-angled 

 but essentially wingless, each internode on the fertile side with a niche into which 

 fits an angle of the achene; scales about 2 mm. long, much-overlapping, with 

 about 3 nerves crowded in the arcuate keel-like median, otherwise smooth and 

 shiny, deciduous; stamens 2; achene lenticular (biconvex) about 1 mm. long, 

 elliptic, apiculate, surficially nearly featureless, ripening through shades of brown 

 to nearly black, oriented so an angle fits into the internode niche. C. melano- 

 stachys H.B.K. 



We have two varieties. 



Var. castaneus (Pursh) Kiikenth. With usually lax elaborate inflorescences. 

 C. bipartitus Torr., C. rividaris Kunth. Rare in moist or wet sandy loam in e. Tex. 

 (Austin and Washington cos.); from Que. w. to Minn, and Neb., s. to Ga., Ala., 

 Miss, and Tex.; also Calif, and Ore. 



Var. capitatus (Britt.) O'Neill. Fig. 218. With relatively light-colored (chestnut- 

 brown) glumes and strongly apiculate achenes. Local in creeks in igneous Trans- 

 Pecos Tex. mts. at elev. of more than 4,000 ft., and Ariz. (Apache, Navajo, 

 Yavapai, Greenlee, Gila, Cochise, Santa Cruz and Pima cos.), summer-fall; from 

 Cuba and C.A. n.w. to Calif., Ariz, and Colorado. 



9. Cyperus odoratus L. Fig. 219. 



Tufted perennial, rarely rhizomatous or often flowering the first year and 

 behaving annual; culms often slightly tuberous-thickened basally, to 9 dm. long, 

 subbasally 1-6 mm. thick, just beneath the inflorescence 0.3-3 mm. thick; inflores- 

 cence 1-45 cm. long, of numerous very unequal spreading or ascending primary 

 peduncles the longer of which usually bear several unequal secondary peduncles, 

 all eventually bearing lax to subdense spikes of rather numerous spreading spike- 

 lets; bracts 3 to 10, the longer far-surpassing the inflorescence; spikelets quite 

 variable in size (about 1 mm. broad and thick) and number of scales (4 to 30), 

 each internode of the axis unilaterally (on the sterile side) postanthetically bulbous 



429 



