42 CYPERACEAE 



Pennsylvania : Dei,aware ; Phii<adei-phia ; Chester ; Bucks ; North- 

 ampton ; Lancaster ; Franklin ; Luzerne ; Huntingdon ; Erie ; 

 Allegheny. 



Family 2. CYPERACEAE J. St. Hil. Sedge Family. 

 Flowers of the spikelets, or at least one of them, perfect. 

 Scales of the spikelets enclosing a bractlet or a pair of bractlets. 



I. Hemicarpha. 

 Scales of the spikelets not enclosing bractlets. 

 Spikelets perfect or mainly so, rarely of 2 scales and i flower. 

 Scales of the spikelets 2-ranked. 

 Perianth present, the members bristle-like. ^. Dulichitjm. 



Perianth wanting. 3. Cyperus. 



Scales of the spikelets spirally imbricated all around. 

 Base of the style not at all or only slightly thickened, deciduous. 

 Perianth-parts conspicuously elongated. 4. Eriophorum. 



Perianth-parts not conspicuously elongated. 5. SciRPUS. 



Base of the style manifestly swollen, persistent as a tubercle on the 

 achene or deciduous. 

 Perianth present. 6. Eleocharis. 



Perianth wanting. 

 Achene not surmounted by a tubercle. 7. Fimbristylis. 



Achene surmounted by a tubercle. 8. Stenophyllus. 



Spikelets polygamous, or rarely of 4 scales and only i flower. 

 Stigmas 3 : style deciduous. 9. Cladium. 



Stigmas 2 : style persistent. 10. Rynchospora. 



Flowers monoecious or dioecious. 

 Achene not enclosed in a utricle (perigynium). 11. Scleria. 



Achene enclosed in a utricle (perigynium). 12. Carex. 



1. HEMICARPHA Nees & Am. 

 1. Hemicatpha micrantba (Vahl. ) Britton. Hemicarpha. (Man. p. 

 183 ; l.'B.f. 646.) In moist sandy soil, R. I. to Pa., Fla., Tex. and Mex. 

 — Pennsylvania : Lycoming, on the Susquehanna ; Erie, Presque Isle. 



2. DULICHIUM L. C. Rich. 

 1. Dulichium arundinacemn (L. ) Britton. Dulichium. (Man. p. 

 167 ; I. F. /. 576.) In wet places, N. S. to Ont., Minn., Fla. and Tex. 

 — Pennsylvania: Pike; Monroe; Lackawanna; Northampton; 

 DELAWARE ; Chester ; Lancaster ; Dauphin ; Franklin ; Luzerne ; 

 Huntingdon ; Erie. 



3. CYPERUS L. 



A. Style-branches or stigmas 2 : achene lenticular. 

 Superficial cells of the achene oblong. i. C.flavescens. 



Superficial cells of the achene quadrate. 

 Scales of the spikelets blunt. 

 Scales membranous, dull : style-branches or stigmas much exserted. 



2. C. diandrus. 

 Scales subcoriaceous, shining : style-branches or stigmas included or 

 scarcely exserted. 3. C. rivularis. 



Scales of the spikelets acute or mucronate. 4. C. Nuttallii. 



