J48 REPORT OF NEW JERSEY STATE MUSEUM. 



CYPERUS L. 



Flozccriiig ami h'niitiiig Data. — The time of year denotes the 

 season ckiring which intact inflorescences, heads, and spikelets 

 of characteristic shape, are present. 



Mature achenes are present some times after the season here 

 designated, but the spikelets are then losing their characteristic 

 shape througii the dropping of the scales. 



Key to the Species. 



a. Spikelets flat, two-ranked and closely imbricated, more than 1.5 mm. 

 wide, sessile in radiating umbels or occasionally one or two secondary 

 umbels on pedicels. 

 b. Edges of the spikelet sharply and finely notched owing to the pro- 

 jecting points of the scales. 

 c. Scales brown with a green keel, tips very sharp, slightly mucro- 

 nate. Head often proliferous. C. dentatus, p. 251 



cc. Scales yellowish brown, tips not mucronate, not proliferous. 



d. Spikelets 2 mm. wide or over ; maritime. C. nuttallii, p. 250 



dd. Spikelets less than 2 mm. wide, usually several short-pedi- 



celled umbels. C. microdontus, p. 251 



bb. Edges of the spikelet nearly entire, the tips of the scales blunt and 



not projecting. 



c. Spikelets yellow or yellowish, 1.5-2.5 mm. broad. 



C. Havescens, p. 249 

 cc. Spikelets brown or green, spotted or bordered with brown. 



d. Spikelets 5-10 mm. long, branches of the styles projecting 

 from the scales, secondary umbels always present. 



C. diandrus, p. 250 

 dd. Spikelets 10-20 mm. long, smooth and shining, style branches 

 rarely visible, secondary spikelets occasional. 



C. rivularis, p. 250 



aa. Spikelets less than 1.5 mm. wide, often terete in cylindrical spikes at 



least one inch long, mostly on peduncles which are usually branched and 



sometimes very compound, forming masses of inflorescence 1-2 dm. or 



more in diameter. 



b. Peduncles branched. 



c. Spikes very dense, scales falling away from the rachis of the 

 spikelet at maturity. C. crythrorhisos, p. 252 



cc. Spikes often loose, scales persistent on the rachis until the spike- 

 let itself falls off. 

 d. Spikelets tertetc, C. speciosns, p. 252 



dd. Spikelets distinctly flattened. C. strigosus, p. 253 



bb. Peduncles not branched. 



c. Lower spikelets not reflcxed, heads rather loose, roots with small 

 root tubers. C. esculentus, p. 252 



