EXPLANATIOX OF PLATE IV. 



DICHROMENA. — (1) Head aud involucre of D. latifolia; (2) a scale 



from one of the spikelets, and (3) the same cut across; (4) a flower; 



(5) achene with its tubercle. 

 PSILOCARYA. — (1) Part of plant, (2) enlarged spikelet, (3) detached scale, 



(4) flower, aud (5) achene with its beak, of P. scirpoides. 

 RHYNCHOSPORA. — (1) Upper part of flowering stem of R. Torreyana; 



(2) a spikelet; (3) detached flower; (4) achene, with short bristles at 



its base ; (5) one of these bristles more magnified. 

 R. (§ CERATOSCHCENUS). — (1) Upper part of fruiting plant, (2) de- 



taclied spikelet, (3j flower, and (4) beaked achene, with its bristles, of R. 



macrostachva. 



