NATL J{ A I. ()110L;KS. 145 



Richard's Hypaolytnmi l)ciiig lateral, or light and left 

 with respect to the axis of the spikelet/ were compared to 

 tliose of the female flowers of Di/j/acr/o//, to the utriculus 

 or ncctarium of Carex, and to the lateral bractcac of Lcpy- 

 rodia, a genus belonging to the nearly related order Kcs- 

 tiaceae.^ But as in Hi/pcelijlrum, according to M. Richard's 

 description, and I believe also in his Dijjla^ia^ there arc 

 sometimes more than two inner squamae, which are then 

 imbricate, they may in both these genera be considered as 

 a spikelet reduced to a single flower, as in several other 

 genera of Cyperacea}, and in Lipocarpha itself, from which, -m 

 however, they are still sufficiently difierent in their relation 

 to the including squama: and to the axis of the spike. 



This view of the structure of Ilypselytrum, of which 

 there is one species in the Congo herbarium, a])pears to 

 me in some degree confirmed by a comparison with that of 

 Chondracltne and Chorizandra ;^ for in both of these genera 

 the lower squamae of the ultimate spikelet are not barren, 

 but monandrous, the central or terminating flower only 

 being hermaphrodite. 



GRAMINEiE. Of this extensive family there are forty- 

 five species from the Congo, or one twelfth of the Phaeno- 

 gamous plants of the collection. This is very nearly the 

 equinoctial proportion of the order as given by 13aron Hum- 

 boldt, namely, one to fifteen, with which that of India 

 seems to agree. On the north coast of Tscw Holland, the 

 proportion is still greater than that of Congo. 



The two ])rincipal ti'ibes which form the far greater part 

 of Gramineac, namely, PoacecB and J?aiiicccE have, as I have 

 formerly stated,' very difierent relations to climate, the 

 maximum both in the absolute and relative number of 

 species of Paniceao being evidently within the tropics, that 

 of Poaccac beyond them. 



I have hitherto found this superiority of Paniceao to 

 Poaceae, at or near the level of the sea within the tropics, 



1 Prodr. Flor. Kov. JIoll. 1, ;;. 219. -' F/imkris Voy. 2, p. 5;9. {Ante, p. 53.) 

 3 Persoo7i S>/)>. PL I, p. 70. •» Prodr. Flor. Nov. lIolL \,p. 220. 



'" Prodr. Flor. Nov. lloll. 1, p- 109. Obs. 11. Flinders s Votj. 2, p, 583. 

 i/inlc, p. 58.) 



10 



