Oo- 



CYI'KUACK.K. (si:i)(;i': ia.mii. v.) 



* * * I'eriuiith none : stylu tuiiiiil ut tin- l>;u«.'. 



<- Scales iiubriuuted iu »cver<tl rowij : spikeH terete. 

 U). KIMBKISTVLIS. Style deciduous : stigiuas •_' : nut lenticular or globose. 

 11. TKICHKLOSTVLIS. Style deciduous : stignuiH 3 : nut 3-aiiglcd. 

 I'J. ISOLKl'lS. Style per.sistent at the base : stigmus 3 : nut it-ungled. 



■t- ■>- Si-ales imbricated iu 2 rows : spike compressed. 



13. ABILDG.V.VRDIA. Style 3-cleft, jointed to the 3-ougled nut. 



Tbibe IV. KHYNCHOSPORE.^. Flowers perfect or polygamous : spikelets com- 

 mouly few-flowered : scales one to each flower, imbricated in few - several rows, the 

 lower ones empty, the upper mostly sterile ; periantli bristly, or none. 

 * Perianth bristly (occasionally wanting in Rhynchospora). 



14. RHYNCHOSPORA. Style 2-eleft or entire, dilated and persistent at the base : nut len- 



ticular or globose. 



15. CH.ETOSPORA. Style 3-cleft, deciduous : nut 3-angled : spikelets terminal. 



* * Perianth none. 

 IC. PSILOCARYA. Spikes terete, many-flowered, cymose : flowers perfect. 



17. DICHROMENA. Spikes compressed, capitate : most of the flowers imperfect. 



18. CLADIUM. Spikes few-flowered, only the uppermost flower perfect : nut globose. 



Tribe V. SCLERIE^. Flowers monoecious : sterile spike many-flowered : scales 

 one to each flower, imbricated iu few rows : fertile spike 1-flowered, with two or 

 more scales : perianth none. 



19. SCLERIA. Style 3-cleft, deciduous. Nut bony, globose or 3-angled. 



Tribe VI. CARIC£.i£< Flowers monoecious, very rarely dioecious : sterile and fer- 

 tile flowers on the same spike, or on separate spikes : scales one to each flower, 

 imbricated in few - many rows : nut enclosed in a sac : periantli none. 



20. CAREX. Bristles within the sac none. Spikes axillary and terminal. 



1. CYPERUS, L. 



Spikelets 2 -many-flowered, commonly flat or compressed. Scales imbri- 

 cated in two opposite rows, often decurrent on the jointed rachis, deciduous. 

 Perianth none. Stamens 1-3. Style 2 - 3-cleft, deciduous. Nut lenticular 

 or 3-aiigled. — Culms 3 angled (rarely terete), jointless, leafy or occasionally 

 sheathed at the base. Spikelets numerous (rarely 1-2), disposed in single 

 or umbellate heads or spikes, and surrounded with a leafy involucre. Rays 

 sheathed. 



§ 1. Pycrecs. — Stijle 2-clefl: nut lenticular. 



* Spikelets clustered on the common rachis, or capitate. 



1. C. flavescens, L. Umbel sessile or of 2-4 rays, shorter than the 

 spikelets; spikelets 3 -.several in a cluster, oblong-linear, acute, spreading, 

 20 - 30flowered ; scales yellowish brown, ovate, obtuse, appressed; rachis 

 margined ; stamens 3; nut orbicular, black, smooth or papillose; culms clus- 

 tered, 4'- 10' high; leaves and 3-leaved involucre narrowly linear. — Low 

 grounds. July- Augu.st. 



2. C. diandrus, Torr. Uml)el of 2-5 .short and unequal ray.s, the 

 longer ones longer than the spikelets; spikelets lanceolate-oblong, acute, 

 brownish or dark brown, spreading ; scales ovate, obtuse, appressed, green on 

 tlie keel ; rachis margined ; stamens 2 ; nut oblong-obovate, rougliish, dull 



