Page:Miscellaneousbot01brow.djvu/150

132 ovarium entirely distinct from the calyx; its capsule in appearance and deliisccnce is exactly like that of Bursaria.

The existence of this genus tends to confirm what I have formerly asserted respecting the want of satisfactory distinguishing characters between these two orders, and to prove that they belong to one natural class; the ovarium superum approximating it to Apocineæ; the interpetiolary stipules and structure of seeds connecting it, as it appears to me, still more intimately with Rubiaceæ.

The arguments adduced by M. de Jussieu for excluding Usteria from Rubiaceæ and referring it to Apocineæ, are, its having ovarium superum, an irregular corolla, fleshy albumen, and only one stamen; there being no example of any reduction in the number of stamina in Rubiaceæ, (in which Opercularia and Pomax are not included by M. de Jussieu) while one occurs in the male flowers of Ophioxylum, a genus belonging to Apocineæ. From analogous reasoning he at the same time decides in referring Gærtnera of Lamarck to Rubiaceæ, though he admits it to have ovarium superum; its flowers being regular, its albumen more copious and horny, and its embryo erect. But all these characters exist in the new genus from Congo. These two genera therefore, together with Pagamea of Aublet, Usteria, Geniostoma of Forster (which is Anasser of Jussieu) and Logania, might, from their mere agreement in the situation of ovarium, form a tribe inter- 449] mediate between Rubiaceæ and Apocineæ. This tribe, however, would not be strictly natural, and from analogy with the primary divisions admitted in Rubiaceæ, as well as from habit, would require subdivision into at least four sections: but hence it may be concluded that the only combining character of these sections, namely, ovarium superum, is here of not more than generic value; and it must be admitted also that the existence or absence of stipules is in Logania of still less importance.