366 MB. G. BENT HAM ON CYPEEACE^. 



and the hypogynous disk or gynophore as that of Scleria, there 

 has been much uncertainty as to the smaller genera, where these 

 characters are modified or evanescent, or which for other reasons 

 could not be united with either of the larger ones. The genus 

 Trilepis of Nees was founded upon two species, which have but 

 very little in common besides their unisexual flowers ; and it has 

 not been improved by the additions made to it by Boeckeler. The 

 affinities of Kobresia have been studied only with relation to 

 Carex, whieh it approaches in habit, but little in character. The 

 fact also of the nut being enclosed in a utricle has been taken as 

 too absolute a character, without considering that that utricle is 

 evidently very different in structure in Hoppia and in Carex, and 

 that it passes into an ordinary glume in some of the species 

 usually referred to Scliosnoxiphittm or to Kobresia, which I have 

 collected under the name of Hemicarex. To me it appears that 

 the relative position of the male and female flowers or spikelets 

 in the inflorescence affords more natural as well as more definite, 

 though not always quite definite, tribual and generic characters. 



In all Cyperaceae with strictly unisexual flowers, where the 

 spikelets themselves are unisexual, the females are always 1- 

 flowered, the males often many-flowered, very rarely 1- or 2- 

 flowered. "Where the spikelets are androgynous they contain 

 only one female but several male flowers. Their relative arrange- 

 ment supplies the chief characters of the following tribes : — 



1. Cryptangie.e. — Spikelets unisexual, the females either ter- 

 minal, closely surrounded by males, or scattered in the upper part 

 of the inflorescence. The following eight genera are all from 

 tropical America : — 



* Spikelets loosely paniculate, all separate or the males in little 

 clusters : Lagenocarpus, Nees, and Cryptangium, Nees (including 

 Acrocarpus). 



** Spikelets very small and sessile, collected in androgynous 

 heads or oblong spikes, the females uppermost or central in each 

 head or cluater : Fintelmannia, Kunth {Trilepis, Nees, as to the 

 Brazilian species), Cephalocarpus, Nees, and Pteroscleria, Nees. 

 To the latter genus I would refer the Scleria capitata, Willd., 

 placed by Boeckeler in Diplacrum, if I am right in identifying 

 with it Spruce's n. 3763 from Venezuela. 



*** Spikelets minute, in small androgynous clusters, collected 

 in heads or corymbs, each cluster with a single female spikelet 

 surrounded by very few males : C'alyptrocarya, Nees, the female 



