filaments often less readily caducous than the scales); scales 1.2-1.6 mm. long, 

 0.8-1 mm. broad, obtuse, fragile-membranous, 3-nerved (actually with 5 nerves 

 but the ones nearest the margin extremely inconspicuous and in some specimens 

 weakly developed); stamens 3; achene globose-obovate to subglobose, obscurely 

 trigonous, 0.4-0.7 mm. long, 0.4-0.5 mm. thick, whitish, roughened. Incl. var. 

 americanus Boeck., C. juncoides Lam. 



Infrequent in moist places, in water of swift stream, in wet meadows, on 

 seepage slopes, in e. and s.e. Tex. and coastal parts of Rio Grande Plains, inland 

 to Guadalupe Co., June-Oct.; widely distributed in warm regions. 



24. Cypenis giganteus Vahl. 



Perennial, densely tufted, culms 4-15 dm. long; leaves reduced to mere long 

 brown sheaths at the base of the culm; inflorescence an umbel-like aggregation of 

 10 to 25 primary peduncles (the longest only about twice as long as the shortest), 

 each bearing an umbellule of 4 to 8 peduncled lax spikes with elongate axes and 

 10 to 20 (reportedly up to 50) spreading spikelets; spikelets about 1 mm. broad 

 or narrower, laterally much-compressed, 4-10 mm. long, with 8 to 18 flowers; 

 bracts of umbel about as many as the primary peduncles and surpassing the umbel; 

 bracts of umbellules as many as the spikes and mostly exceeding them; spikelet 

 axis persistent as a unit after the achenes and scales fall; lower margins of scales 

 decurrent on the spikelet axis as hyaline readily deciduous wings 0.2-0.3 mm. 

 broad and more than 1 mm. long; stamens 3; anthers with 2 cells, the connective 

 between the cells prolonged 0.2-0.5 mm. beyond the end of the anthers; achene 

 unequally trigonous, the 2 adaxial angles much smaller (sharper) than the abaxial 

 one. 



Rare in extreme s.e. Tex. (Orange Co.) in marshes, probably not a persistent 

 member of our flora; Parag., Urug. and Col. n. to Hond. and Gr. Ant. 



25. Cypenis alternifolius L. Umbrella flatsedge, umbrella plant. 



Tufted perennial; culm 3-15 dm. long, erect, basally 5-20 mm. thick, just below 

 the apex 1-5 mm. thick, triangular; leaves few, basal, reduced to sheaths, apically 

 with a diagonal orifice and a short flat triangular blade 5-50 (-100) mm. long; 

 inflorescence (excluding bracts) 3-10 cm. long, of 15 to 25 slightly unequal 

 primary peduncles each bearing a short headlike raceme of 8 to 15 short- 

 peduncled spikelets; bracts 15 to 25, 15-40 cm. long, 1-15 mm. broad, spreading 

 (forming an umbrella); spikelets 5-10 mm. long, 1.5-2 mm. broad, with 12 to 30 

 flowers, compressed, the axis wingless and remaining intact as a unit after the 

 scales have fallen (achenes often more persistent); scales 1.6-2 mm. long, 1.4-1.6 

 mm. broad when unfolded, several-nerved; stamens 3; achene trigonous, 0.6-0.9 

 mm. long, 0.5-0.6 mm. thick, brown, elliptic-oblong. 



S.e. Tex., cult, in moist or wet ground and rarely escaping, summer-fall; nat. 

 of the Old World, probably Afr. or Madag., widely cult, and escaping in warm 

 regions. 



26. Cypenis erythrorhizos Muhl. Fig. 229. 



Tufted annual or becoming a definite perennial in s. Tex.; culms 5-14 dm. long; 

 inflorescence an umbel-like aggregation of 4 to 10 long markedly unequal pedun- 

 cles each bearing an irregular cluster of several nearly sessile spikes with elongate 

 axes (with internodes 0-0.5 mm. long) and 15 to 70 spreading spikelets; spikelets 

 about 1 mm. broad or narrower, laterally much-compressed, very thin, 3-10 

 (-15) mm. long with 6 to 34 or more flowers; bracts of umbel about as many 

 as primary peduncles and some about as long as the inflorescence; bracts of 

 the spike clusters considerably reduced, inconspicuous; spikelet axes persistent as 

 a unit after the achenes and scales have fallen; scales keeled, the lower margins 

 decurrent on the spikelet axis as readily deciduous hyaline wings about 0.8 mm. 



447 



