3io 



CYPERACEAE. 



Vol. I. 



37- Cyperus globulosus Aubl. Baldwin's Cy- 

 perus. Fig. 757. 



C. globulosus Aubl. PI. Guian. 1 : 47. 1775. 

 Mariscus echinatus Ell. Bot. S. C. & Ga. 1 : 75. 1816. 

 Cyperus Baldwinii Torr. Ann. Lye. N. Y. 3 : 270. 1836. 

 Cyperus echinatus Wood, Class-book 734. 1863. 



Perennial by tuber-like corms, culm slender, smooth, 

 erect, mostly longer than the leaves. Leaves pale 

 green, 1V-2" wide, those of the involucre 5-10, the 

 longer usually much exceeding the umbel; umbel 

 simple, 6-13-rayed, the rays filiform, their sheaths 

 short, mucronate; spikelets 2"-3" long, linear, flat, 

 densely or loosely capitate in globose heads ; scales thin, 

 pale green, appressed, ovate-lanceolate, acute, 9-13- 

 nerved, with narrow scarious margins; joints of the 

 rachis broadly winged; stamens 3; style 3-cleft; achene 

 oblong-obovoid, obtuse, one-half as long as the scale, 

 about twice as long as thick. 



In dry soil, sometimes a weed in cultivated fields, Vir- 

 ginia to Florida, west to Missouri and Texas. Also in Ber- 

 muda and in tropical America. July-Aug. 



3, ELEOCHARIS R. Br. Prodr. Fl. Nov. Holl. 1 : 224. 1810. 



Annual or perennial sedges. Culms simple, triangular, quadrangular, terete, flattened or 

 grooved, the leaves reduced to sheaths or the lowest very rarely blade-bearing. Spikelets 

 solitary, terminal, erect, several-many-flowered, not subtended by an involucre. Scales con- 

 cave, spirally imbricated all around. Perianth of 1-12 bristles, usually retrorsely barbed, 

 wanting in some species. Stamens 2-3. Style 2-cleft and achene lenticular or biconvex, or 

 3-cleft and achene 3-angled, but sometimes with very obtuse angles and appearing turgid. 

 Base of the style persistent on the summit of the achene, forming a terminal tubercle. 

 [Greek, referring to the growth of most of the species in marshy ground.] 



About 140 species, widely "distributed. Besides the following, some 20 others occur in the 

 southern and western parts of North America. Type species : Scirpus palustris L. 



1. Spikelet scarcely or not at all thicker than the culm ; scales coriaceous. 

 Culm stout ; spikelet many-flowered. 



Culm terete, nodose. 1, E. interstincta. 



Culm quadrangular, continuous. 2. E. mutata. 



Culm slender, triangular, continuous ; spikelet few-flowered, subulate. 3. E. Robbinsii. 



2. Spikelet manifestly thicker than the culm (except in No. 13) ; scales membranous. 

 *Style mostly 2-cleft ; achene lenticular or biconvex. 



Upper sheath scarious, hyaline ; plants perennial by slender rootstocks. 



Scales pale green or nearly white; achene J4" long. 4. E. flaccida. 



Scales dark reddish-brown; achene yi" long. 5. E.olivacea. 



Upper sheath truncate, oblique or toothed, not scarious. 

 Annual, with fibrous roots. 

 Achene jet black. 



Culms 1 '-3' tall ; achene J4" long; bristles 2-4. 

 Culms 3'-io' tall; achene y 2 " long; bristles 5-8. 

 Achene pale brown. 



Spikelet ovoid or oblong. 



Tubercle narrower than the top of the achene. 

 Tubercle about as broad as the top of the achene. 

 Spikelet oblong-cylindric ; tubercle broad, low. 

 Perennial by horizontal rootstocks. 

 Scales pale green to straw-color. 

 Scales brown to purple-brown. 



Tubercle flattened-conic ; spikelet thicker than the culm. 12. E. palustris. 



Tubercle swollen, bulb-like; spikelet not thicker than the culm. 13. E.Smallii. 

 **Style 3-cleft ; achene 3-angled or turgid. 

 Achene reticulated or cancellate. 



Spikelet compressed ; culm filiform. 

 Spikelet terete ; culm slender. 



Achene transversely cancellate ; bristles none.. 

 Achene reticulated ; bristles present, stout. 



Tubercle conic, smaller than the achene. 16. E. simplex. 



Tubercle cap-like, as large as or larger than the achene. 17. E. tuberculosa. 



Achene smooth or papillose. 



Achene smooth, white ; culm9 capillary. 

 Achene papillose or smooth, brown, black or yellow. 

 Tubercle depressed or short-conic. 

 Achene smooth. 



Tubercle flat, covering the top of the black achene. 19. 



Tubercle ovoid-conic, acute, contracted at the base. 20. 



Achene papillose. 



Achene 3-ribbed on the angles. 21. 



Achene obtuse-angled, not ribbed. 



6. E. atropurpurea. 



7. E. capitata. 



8. E. ovata. 



9. E. obtusa. 



10. E. Engelmanni. 



11. E. macrostachya. 



14. E. acicularis. 



15. E. Wolfii. 



18. E. Torreyana. 



E. melanocarpa. 

 E. albida. 



E. tricostata. 



