532 CYPEKACE.E. (SEDGE FAMILY.) 



* * * Perianth none : style tumid at the base, 

 i- Scales imbricated in several rows : spikes terete. 



10. FIMBRISTYLIS. Style deciduous : stiguias 2 : nut lenticular or globose. 



11. TRICHELOSTYLIS. Style deciduous : stigmas 3 : nut 3-angled. 



12. ISOLEPIS. Style persistent at the base : stigmas 3 : nut 3-angled. 



(- -i- Scales imbricated in 2 rows : spike compressed. 



13. ABILDGAARDIA. Style 3-cleft, jointed to the 3-augled nut. 



TRIBE IV. RHYNCHOSPORE^E. Flowers perfect or polygamous : spikelets com- 

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

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

 * Perianth bristly (occasionally wanting in Rhynchospora). 



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



ticular or globose. 



15. CHJ5TOSPORA. Style 3-cleft, deciduous : nut 3-angled : spikelets terminal. 



* * Perianth none. 

 1G. 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 in 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. CARICE^]. 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 : perianth 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-angled. 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. PYCRKUS. Style 2-cleft: 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 - 30-flowered ; 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 -August. 



2. C. diandrus, Torr. Umbel of 2-5 .short and unequal rays, the 

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

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

 the keel ; rachis margined ; stamens 2 ; nut oblong-obovate, roughish, dull 



