CYPERACE.E. (SEDGE FAMILY.) 505 



8. SCIRPUS. Tubercle none : culms mostly leafy at the base or throughout : spikes com- 



monly few or many : perianth of 3 - 6 bristles. 



9. KRIOPHORUM. Perianth of numerous long and woolly hairs : otherwise like Scirpus. 



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

 -i- Scales imbricated in several rows : spikes terete. 



10. FIMBRISTYLIS. Style deciduous : stigmas 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. 



t- 4- Scales imbricated in 2 rows : spike compressed. 



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



TRIBE IV. RII YNCHOSPORE^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, dilated and persistent at the base : nut lenticular or 



globose. 



15. CERATOSCIKENUS. Style entire or minutely 2-cleft, the lower half persistent : nut flat. 



16. CH^TOSPORA. Style 3-cleft, deciduous : nut 3-angled : spikelets terminal. 



* * Perianth none. 



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



18. DICHROMEXA. Spikes compressed, capitate : most of the flowers imperfect. 



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



TRIBE V. SCLERIE^E. 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. 



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



TRIBE VI. CARICE.E. Flowers monoecious, very rarely dioecious : sterile and fertile 

 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. 



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



1. CYPEBUS, L. 



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

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

 none. Stamens 1 - 3. Style 2 - 3-cleft, deciduous. Nat 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. PYCREUS. Style 2-ckft : nut lenticular: spikes more or less umbeUed. 

 Annuals: spikelets linear or linear-oblong, fiat, many- (10-40-) flowered: 

 rachis narrowly margined: scales compressed-keeled, 5-nerved. 



* Spikelets clustered on the common rachis. 



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, and shining; culms clustered 4' -10' 



43 



