EXPLANATION OF PLATE IV. 



DICHROMENA. — (1) Head and iuvolucre of D. latifolia ; (2) a scale 

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

 (5) achene with its tubercle. 



PSILOCARYA. — (1) Part of j^lant, (2) enlarged spikelet, (3) detached scale, 

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



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

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

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



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

 tached spikelet, (3) flower, and (4) beaked achene, with its liristles, of R. 

 macrostacliva. 



