OF CENTRAL AFRICA. 287
insertion of the funicnlus, its radicle being seated at the opposite extremity of the seed, or to express, in the iniiiu- pregnated ovarium, the infallible indication of this 12^2 ])ositionj the direction of the inner mem])rane and nucleus of the ovulum corresponds with that of its testa.
But this character, in general very uniform in natural families, and which, equally existing in Cistineae, so well defines the limits of that order, as I have long since remarked/ would seem to be of less importance in Zygo- phyllea^.
M. Adrien de Jussieu, who, in his memoir already cited, admits its existence in Fagonia, and in both our species of Zygophyllum, considers it as an exception to the general structure of the latter genus, in the definition of which he retains the character of "radicula hilo proxima." I believe, however, that in all the species of Zygophyllum, except Fabago, which, possesses, also, other distinguishing cha- racters, this opposition of the radicle to the external hiluni will be found ; for in addition to the two species contained in the herbarium, in both of which it is very manifest, I have observed it in Z. coccineum, and in all the species of South Africa that I have had an opportunity of examining. In some of these species, indeed, it is much less obvious, partly from the greater breadth of the funiculus, and also from its being closely applied, or even slightly adhering to the testa of the seed. But hence it is possible to reconcile the structure of these species with that of Fabago itself, in which the raphe seems to nie to be external : and if this be really the case, Fabago differs from those Zygophylla of South Africa alluded to, merely in the more intimate imion of the funiculus with the surface of the testa. AVhether this observation might be extended to the other genera of the order, I have not yet attempted to ascertain.
Balanites yEoYPTiACA, thouo;h not belonc-insf to Zv2:o- j)hylleae, may be here mentioned. The specimen is from Bornon, but, like all the other plants of that country, has no particular place of groAvth indicated, nor is there any
��In Iloo/icr^s Flora Scotica, p. 284.
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