44 CYPERACEAE. 



Style 3-cleft, its base fused with the top of the achene ; 

 tubercle none. 

 Bristles none. 9. Marisoua. 



Bristles present. 10. Schoenvs. 



Flowers all imperfect: achene bony or crustaceous. 11. Scleria. 



1. CYPERUS L. Sp. PI. 44. 1753. 



Annual or perennial sedges. Culms in our species simple, triangular, leafy 

 near the base, and with 1 or more leaves at the summit forming an involucre 

 to the simple or compound, umbellate or capitate inflorescence. Rays of the 

 umbel sheathed at the base, usually very unequal, one or more of the heads or 

 spikes commonly sessile. Spikelets flat or subterete, the scales falling away 

 from the rachis as they mature (nos. 1-7), or persistent and the. spikelets 

 falling away from the axis of the head or spike with the scales attached 

 (nos. 8-14). Scales concave, conduplicate or keeled, 2-ranked, all flower-bear- 

 ing or the lower ones empty. Flowers perfect. Perianth none. Stamens 1-3, 

 Style 2-3-cleft, deciduous from the summit of the achene. [Ancient Greek 

 name for these sedges.] About 600 species, of wide distribution in tropical 

 and temperate regions. Type species: Cyperus esculentus L. 



Style-branches 2 ; achene lenticular. 1. C paniculatus. 



Style-branches 3 ; achene trigonous. 



Spikelets not breaking up into one-fruited joints. 



Scales deciduous from the persistent rachis of the 

 spikelets. 

 Rachis-wings none, or very narrow. 

 Annuals. 



Scales tipped with recurved awns. 

 Scales acuminate, not awned. 

 Perennials. 



Leaves flat : plants not viscid. 



Spikelets yellow, oblong-lanceolate. 

 Spikelets green-brown, ovate. 

 Leaves involute ; plant viscid. 

 Rachis-wings manifest ; perennial. 

 Spikelets falling away above the two persistent lower 

 scales. 

 Leaves and culms filiform, reclining. 

 Leaves flat ; culms stout or slender, erect. 

 Spikelets with 1-4 achenes. 



Spikelets in a single capitate cluster. 

 Umbel compound : spikes cylindric. 

 Spikelets with 5-20 achenes. 



Scales acute or cuspidate, not awned. 

 Scales awned. 

 Spikelets breaking up into one-fruited joints. 

 Umbel compound : annual with flat leaves. 

 Spikelets in a single cluster or two ; perennial with 

 filiform leaves. 



1. Cyperus paniculatus Rottb. Deser. & Icon. 40. 1773. 



Cyperus Gatesii Torr. Ann. Lye. N. Y. 3: 255. 1836. 



Annual, bright green. Leaves 1-4 mm. wide; culms slender, tufted, 1-4 

 dm. tall, often surpassing the leaves; bracts of the involucre 3-5, surpassing 

 the umbel, the longer ones up to 2 dm. long; umbel with 3-8 rays, or rarely 

 nearly capitate: spikelets few, linear or linear-lanceolate, 6-15 mm. long, acute; 

 scales light chestnut-brown, oblong-lanceolate, acute, shining, striate, deciduous 

 at maturity; style 2-cleft; achene lenticular, oblong, grayish, abruptly apicu- 

 late, fully half as long as the scale. 



Moist ground, New Providence : southeastern United States : West Indies ; 

 tropical continental America. Referred by Clarke to Pycraeus ferrugineus ; recorded 

 by Dolley as C. polystachyus Rottb. Paniclkd Cyperus. 



