From this description it is obvious that, with the single exception of the contents of the seed, we are in possession of all that it is essential to know of the structure of this plant. The next subject of consideration is its affinity.
The stellate pubescence, the thickening of the petiole at the point where it expands into the lamina, the station of the stamens upon a long, filiform torus, the external position of the [p111] antheræ, and the union of the filaments by threes into a cup surrounding the ovarium, are all characters that forcibly call to recollection the genus Sterculia. The calyx, indeed, in that genus is generally divided much more deeply than in the plant now under consideration, and the antheræ are usually seated at the base of the ovarium; but, on the other hand, in Sterculia colorata of Roxburgh, which, if a distinct genus, (ERYTHROPSIS) as I am inclined to believe; is nevertheless next of kin to Sterculia, the calyx is of the same figure and divided in the same degree, and the antheræ are also combined in a capitate cup inclosing the ovarium. If, however, we pursue this comparison further we find that, with the characters now adverted to, the similarity ceases; in Sterculia there are no petals, the calyx has a valvular not imbricate æstivation, the cells of the fruit separate into distinct folliculi, and do not combine into a solid woody capsule, and the seeds are destitute of wings.
The fruit suggests so obviously some affinity with Pterospermum, that it is next necessary to institute a comparison with that genus. Stellate pubescence, a calyx divided into five portions, five hypogynous unguiculate petals, and fifteen fertile stamens united into a cup, seated on a stipitiform torus, and surrounding the ovarium, a five-celled ovarium, a woody five-celled capsule, with a loculicidal dehiscence, no axis, and winged seeds; all these characters are common to Pterospermum and our plant; but on the other hand the points in which they differ are of much importance. The æstivation of Pterospermum is valvate recurved not imbricate; its calyx is five-parted, not four—five-toothed; its anthers have parallel not divaricating cells, and are seated upon long distinct filaments, not sessile, upon the outside of a capituliform cup; and finally the petioles of the leaves are not connected with the lamina by a thickened space. The seeds are also winged at the apex, not at the base, but upon this point it is not my wish to insist.