including bracts) 1-7 cm. long, either of a single nearly sessile head or an umbel- 

 like aggregation of 2 to 6 very unequal peduncles each bearing a head of more 

 or less spreading spikelets, the total inflorescence with 5 to 38 spikelets; bracts 3 

 to 5, the longer ones far-surpassing the inflorescence; spikelets 10-24 mm. long, 

 2-3 mm. broad, laterally compressed, with 12 to 24 flowers, the axis persistent 

 and remaining intact even after the achenes and scales have fallen; scales 3-3.5 

 mm. long, acuminate, the keel-like median somewhat excurved in the distal half 

 and with 9 to 13 nerves, grayish-white with very pale broad hyaline margins (so 

 the entire spikelet appears to have a white mid-stripe), decurrent below as 

 definite wings but these persistent until the scale next below falls; stamens 3; 

 achene trigonous, 1-1.3 mm. long, almost as thick as long. 



In moist or wet sand and swampy ground, in Okla. (McCurtain Co.), in- 

 frequent in s.e. Tex., rare in e. Tex., July-Sept.; Afr., Madag., s.e. Asia, Malaysia, 

 N. Austral., Micronesia; in Am. from Ecu., Bol. and Braz. n. to N.Y., Pa., O., 

 Okla. and Tex. 



30. Cyperus Parishii Britt. 



Perennial sedge with short rhizomes and fibrous roots; culms subtrigonous, 

 smooth, 10-25 cm. tall; leaves several, much shorter than the culm, 3-5 mm. 

 wide, minutely scabrellate on the margins and midrib; involucral leaves 3 or 4, 

 scabrellate; inflorescence umbellate, the rays 0.5-5 cm. long; spikelets linear, 

 acute, 12-20 mm. long, about 2 mm. wide; rachis with a pair of hyaline wings at 

 each node, these early deciduous; scales ovate, acute, 2-3 mm. long, strongly 

 several-nerved, the keel green and the sides reddish brown; stamens 3; style 

 trifid; achene trigonous, obovoid-ellipsoid, 1-1.2 mm. long, mucronulate, nearly 

 black. 



Wet meadows in N.M. (Dona Ana Co.) and Ariz. (Yavapai, Maricopa and 

 Cochise cos.) ; N.M., Ariz, and Calif. 



31. Cyperus filiculmis Vahl. Fig. 231. 



Tufted or very loosely tufted perennial; culms basally tuberous-thickened or 

 with short thick rhizomes, 10-35 (-50) cm. long, subbasally 1-2 (-2.3) mm. 

 thick, just beneath the inflorescence 0.5-1 mm. thick; leaves 1-2 mm. broad, even 

 the longer ones mostly shorter than the culms; inflorescence 1-3 cm. long, of a 

 single nearly spherical head of 15 to 55 spikelets or (usually in contaminated 

 plants) the inflorescences with such a head plus a few peduncles 1-5 cm. long 

 each with a head or glomerule of 8 to 20 spikelets; bracts 3 or 4, 0.5-1 mm. 

 broad, much-exceeding the inflorescence, usually spreading or reflexed; spikelets 

 6-16 mm. long, 2.5-4 mm. broad, about 1 mm. thick, grayish-brown to dark- 

 tawny-grayish-brown, with 7 to 20 scales (the terminal one sterile or staminate 

 and slightly reduced), straight, the axis noticeably dorsiventrally flattened, at 

 maturity either persistent or commonly tardily deciduous as a unit from the head 

 axis, the flat sculptured internodes commonly wingless or with wings only to 0.2 

 mm. broad; scales spreading at a 45° angle (the spikelet axis thus exposed), most 

 much-overlapping, 2.5-3.5 mm. long, 2-2.5 mm. broad, broadly ovate, with 9 to 

 11 nerves; stamens 3: achene 1.5-2.2 mm. long, 0.8-1.1 mm. thick, broadly 

 oblong, trigonous, dark-brown. C. Houghtonii Torr. var. Bushii (Britt.) Kiikenth. 



Infrequent, scattered in seasonally moist sandy loam in open-wooded areas, 

 wet sandy banks, in drying stream beds, in Okla. (Alfalfa Co.), n.-cen. Tex., 

 Plains Country and Edwards Plateau, rare in the Trans-Pecos (i.e., genetically 

 dilute plants in Glass Mts.), spring-fall; e. U.S. and s.e. Can. w. to the Rocky Mts. 



32. Cyperus elegans L. Fig. 232. 



Tufted perennial; culms 3-7 dm. long, erect; leaves viscid, crowded near the 

 base, basally stramineous and somewhat spongy when fresh and upon drying the 



451 



