Richard's Hypælytrum being lateral, or right and left with respect to the axis of the spikelet,1 were compared to those of the female flowers of Diplacrum, to the utriculus or nectarium of Carex, and to the lateral bracteæ of Lepyrodia, a genus belonging to the nearly related order Restiaceceæ.2 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 different 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.
GRAMINEÆ. Of this extensive family there are forty-five species from the Congo, or one twelfth of the Phaenogamous 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.)
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