Scarce in shaded moist ravines high in the Chisos Mts. in the Tex. Trans-Pecos 

 and Ariz. (Cochise and Santa Cruz cos.), summer; Venez., Guat., Mex., Ariz, 

 and Tex. 



16. Cypenis acuminatus T. & H. Fig. 224. 



Short-lived perennial, flowering the first year, tufted; culms 1-4 dm. long, 

 erect, basally with a few leaves and 0.7-1.2 mm. thick, just beneath the inflores- 

 cence 0.4-0.8 mm. thick, roundly triquetrous, smooth or with more or less 

 abundant microscopic knobs more or less at right angles to the culm; leaves few, 

 0.5-2 mm. broad, the longer ones sometimes equaling the culms, basally not sep- 

 tate; inflorescence (excluding bracts) 2-8 cm. long, of 2 to 5 very unequal pri- 

 mary peduncles, the shorter of which bear nearly hemispherical to spherical 

 glomerules of 13 to 25 spikelets, the longer ones with such glomerules (rarely 

 compound or with secondary peduncles) of up to 55 spikelets; bracts 3 or 4, the 

 longer ones nearly erect and far-surpassing the inflorescence; spikelets 4-10 mm. 

 long, 1.5-2.5 mm. broad, nearly linear, with 12 to 44 flowers, stramineous to 

 brownish-stramineous or rarely tawny-stramineous, laterally compressed, the 

 axis slightly flattened, wingless and persistent as a unit after the scales and achenes 

 have fallen; scales laterally membranous, inconspicuously cellular, medially firm- 

 membranous. 1.3-1.9 mm. long, in the proximal fifth to fourth the length with a 

 flattish area about 0.2 mm. broad dorsally (abaxially), the 2 lateral parts 0.4-0.6 

 mm. broad (the scale spread out 0.8-1.2 mm. broad, ovate or narrowly so), 

 tapering distally to the acute apex, with 3 nerves (the inconspicuous midnerve 

 plus on each side a conspicuous nerve about three eighths to two fifths the dis- 

 tance from the midnerve to the margin), the dorsal (median) portion of the 

 scale (as the scale is folded in position in the spikelet) incurved in the lower part, 

 in the distal part either straight or usually with a slight to marked excurvature so 

 that the whole is weakly S-shaped; stamen 1; achene elliptic, 0.9-1.1 mm. long, 

 0.35-0.45 mm. thick, sharply trigonous, basally short-stipitate. apically prolonged- 

 acuminate, pale-brown, occasionally maturing to brown. C. cyrtolepis T. & H. 



Abundant in moist places, wet soil and sandy shore of lakes and ponds, and 

 in shallow water, in Okla. (Stephens, Love, Ottawa, Comanche, McCurtain and 

 Mayes cos.), e., s.e., n.-cen. Tex. and Rio Grande Plains, rare in Edwards Plateau 

 (Central Mineral Region only) and the Trans-Pecos (Jeff' Davis and Presidio cos.) 

 and Ariz. (Graham, Gila, Cochise and Pima cos.), almost all year; Mo. and 

 N.C., s. to La., Tex. and Coah.; also Ga., Ariz., Nev., Calif, and Ore. 



Young specimens strongly simulate dwarf specimens of C. reftexiis. 



17. Cypenis surinamensis Rottb. Fig. 225. 



Short-lived tufted perennial, flowering the first year; culms 1-4 (-8) dm. long, 

 with scattered microscopic rctrorse projections like shark's teeth, erect, basally 

 with a few leaves and 0.8-3.5 (-4.5) mm. thick, just beneath the inflorescence 

 0.4-1.5 mm. thick and bluntly triquetrous; leaves few, the longer ones nearly as 

 long as the culm, basally usually with scattered microscopic transverse septa be- 

 tween the nerves; inflorescence (excluding bracts) 1-8 cm. long, of (4 to) 7 to 12 

 very unequal primary peduncles the shorter of which bear nearly spherical 

 glomerules of 8 to 25 spikelets, the longer usually with several very unequal 

 secondary peduncles each with a nearly spherical head of 11 to 35 spikelets; 

 bracts 5 to 7, the longer ones far-surpassing the inflorescence; spikelets 3-6 (-14) 

 mm. long, 1.8-2.5 mm. broad, nearly linear, with 10 to 20 (to 30) flowers, 

 stramineous to chartreuse or ochraceous, laterally compressed, the axis slightly 

 flattened, wingless and persistent as a unit after the scales and achenes have fallen; 

 scales laterally membranous, inconspicuously cellular, medially slightly firmer, 

 1-1.5 mm. long, in the proximal third to three fifths the length with a flat abaxial 

 (dorsal) area 0.15-0.2 mm. broad, the 2 lateral parts 0.4-0.6 mm. broad (the 



438 



