430 NATURAL HISTOBY OF PLAXTS. 



verticels of stamens, five of which are alternipetalous aucl longer ; 

 each formed of a free filament and an introrse anther whose two cells 

 are dilated outwardly in a sort of wing and open by a longitudinal 

 slit. The gynteceum is composed of three independent carpels, col- 

 located round the centre of the receptacle, each being formed by a 

 unilocular ovary and a subulate style, stigmatiferous towards its 

 tapering summit, and whose base is inserted, according to age, more 

 or less low on the internal edge of the ovary. This latter contains 

 in its internal angle an ovule, transversely or more or less obliquely 

 directed, incompletely campylotropous, the micropyle being at first 

 turned upwards and outwards, but frequently displaced later on. 

 The fruit is formed of three achajnes, one or two may be aiTested 

 in their development (fig. 428). Their coat is thick, woody, and 

 each of them is supported by a short foot. Those which are fertile 

 contain a globular seed whose membranous coats cover an embryo 

 with short superior radicle and thin cotyledons, irregularly convo- 

 lute, the inner being usually longer and folded many times upon 

 itself. Only one species of Pterandra^ is known ; it is a Brazilian 

 shrub, all of whose parts are covered with a silky down. The leaves 

 are opposite, entii-e, nearly coriaceous, nearly glabroxis above, covered 

 with down on the inner face, on which is drawn a network of pro- 

 minent nerves. They are accomiDanied by axillary stipules. The 

 flowers" are arranged in the axil of the leaves in umbel liform cymes ; 

 their pedicels are slender and accompanied, at the base or higher up, 

 by two or more bracts. 



Beside Pterandra are placed several closely allied genera : the 

 Acmanthcra, from Brazil, distinguished by the development of the 

 two largo glands which their five sepals bear below and outside ; 

 by their anthers, which, besides the lateral appendages, present a 

 special prolongation of their connective ; and by theii" independent 

 carpels, which become so many sessile utricles, and finally break 

 towards the apex; the Colcostaches^ from Guiana, whose calyx, des- 

 titute of glands, increases after floration, and whose stamens, united 

 by the base of the filaments, are destitute of appendages. Their 

 independent carpels appear indehiscent. The Clonodia, trees from 



• r. pi/i-oidm A. Juss. lue. cit. 71, t. 179 h.— Jvss. lie. cit. 73, t. 179 *. 

 GuiSEU. Mart. Fl. Bras. Malpii/h. 30. — Wali'. - Kosy, tomcntose 



J.''jVV, J5(j; Anit, yW. 4G9. P. jisiiliifolia A. 



