Fig. 242: a, Dichromena colorata: a, achene, X 25 b, Dichromena latifolia: b, 

 achene, X 20. (Courtesy of R. K. Godfrey). 



occasionally reduced to virtual absence; spikelets with several spirally-disposed 

 scales, the axils of the lowest 1 (or 2) scales empty, the 1 to 10 axils above with 

 perfect flowers, and usually above that 1 or 2 scales enclosing staminate or rudi- 

 mentary flowers; scales usually broad, membranous, usually brownish with very 

 indistinct midnerves and no other nervation; bristles usually above 6 or 8 (or up 

 to 20) or reduced to virtual absence; stamens usually 1 or 2 or 3; style bifurcate 

 either at the very tip or usually much farther down, its base becoming indurate 

 and persisting on the achenial body as a tubercle of distinctly difl'erent texture; 

 achenial body usually distinctly biconvex, varying to nearly flat or nearly turgid, 

 the cells of the face usually variously sculptured and elongated, the walls often 

 prominent. 



About 200 species, cosmopolitan in distribution, especially tropical. The name 

 has been misspelled as Rynchospora and Rhyncospora in various works. 

 1. Style nearly simple or very shortly 2-branched at the summit; achenial bodies 

 3.5-6 mm. long; tubercle 3.5-18 mm. long (2) 



1. Style with 2 long branches; achenial bodies and tubercles mostly shorter (4) 



2(1). Mature spikelet 7-10 mm. long; achenial body 3.5-4 mm. long; tubercle 

 3.5-4 mm. long 3. R. indianolensis. 



2. Mature spikelet 15-23 mm. long; achenial body 4—5 mm. long; tubercle 13-18 



mm. long (3) 



3(2). Bristles (at least most of them) much-exceeding the achenial body..... 



1. R. macrostachya. 



3. Bristles shorter than the achenial body, stout and closely appressed 



2. R. corniculata. 



4(1). Achenial bodies pearly-white, 0.7-0.8 mm. long; tubercles 0.1-0.2 mm. 

 long, 0.15-0.2 mm. broad; spikelets with 5 to 8 fertile flowers; 

 perianth bristles absent (5) 



4. Achenial bodies and/ or tubercles considerably larger and often brownish in 



color; spikelets with fewer fertile flowers; perianth bristles usually 

 present (6) 



469 



