n8 



FIELD COLUMBIAN MUSEUM BOTANY, VOL. 2. 



CYPERUS Linn. 



Including Mariscus and Torulinium. Inflorescence in more or less 

 densely disposed subumbellate spikes. Fertile flowers bi-sexual. 

 Rachilla winged or wingless; spikelets few to many fruited; scales 

 distichous, the lower two empty; bristles none. Stamens 1-3. Style 

 3-cleft; achene trilateral: 



Achenes trilateral, styles 3-cleft: 



Surfaces papillate in longitudinal lines C. virens 



Surfaces reticulate 



hexagonally C. ochraceus 



lozenge-shaped C. elegans 



Surfaces reticulate and papillate 



reticulations of faint lines C. brizasus 



reticulations of sharp lines 



papillae small C. ferax 



papillae large C. planifolius 



reticulations of faint ridges C. ligularis 



Surfaces pitted C. Caymanensis 



Surfaces reticulate and pitted 



reticulations of grooved lines C. bruneus 



reticulations of faint raised lines 



pits deep, margin narrowly lipped C. Michauxianus 



pits shallow, margin broadly lipped C. filiforme 



\EUCYPERUS. Spikelets compressed; rachilla persistent on 

 the axis, scale deciduous. 



CYPERUS VIRENS Michx. Flor. Bor. Am., 1:28. 



Cypcrtis Surinamensis Britton, on page 29. 



Bracts leaf-like, 1-2. 5dm. long. Inflorescence a compound umbel; 

 rays about 10, 2-4 cm. long; secondary 

 umbels 2-4-rayed 2 cm. long; bractlets 

 1-2 cm. long. Spikes pale-green, sub- 

 globose, 1-5 cm. wide, composed of 

 10-20 spikelets fascicled upon the re- 

 duced rachis; strongly compressed, nar- 

 rowly ovate, 3x8 mm., 6-2o-fruited; 

 rachilla wingless. Scales white with a 

 green midvein, translucent, loosely cel- 

 lular, oblong-ovate, obtuse, keeled, 

 faintly 3-nerved, twice the length of the 

 achene, closely imbricated. Stamen i, 

 lateral. Style half the length of the 

 achene, divisions short. Achene dull- 

 black, narrowly ellipsoid, I.4X.45-.5 mm., in .section triangular, 

 angles obtuse, dorsal facets slightly convex, the ventral plane; all 

 marked by regular longitudinal lines including single rows of trun- 

 cated conical papillae. 



Wet roadside between Santurce and the sea, Porto Rico (299). 



CYPERUS OCHRACEUS Vahl. Enum., 2:325. 



Bracts leaf-like, 1-4 dm. 'long. Inflorescence a decompound 



