between these relative numbers of stamina and pistilla, and the singular mode of fecundation in this tribe. But in Potalia and Anthocleista, there is a remarkable increase in the number of stamina and segments of the corolla, and at the same time a reduction in the divisions of the calyx. The pistillum in Potalia, however, if my account of it be correct, agrees in division with that of Apocineae; and the deviation from this division in Anthocleista is only apparent; the ovarium, according to the view I have elsewhere given of this organ[1] being composed of two united ovaria, again indeed subdivided by processes of the placenta, but each of the subdivisions or partial cells containing only one half of an ordinary placenta, and that not originating from its inner angle, as would be the case were the ovarium composed of four confluent organs.
Of ASCLEPIADEAE there are very few species in the
collection, and none of very remarkable structure. The
Periploca of Equinoctial Africa alluded to in my essay on
this family,[2] was one of the first plants observed by Professor Smith at the mouth of the river; and a species of
Oxystelma, hardly different from O. esculentum of India,[3]
was found, apparently indigenous, on several parts of its
banks.
The ACANTHACEAE of the collection, consisting of
sixteen species, the far greater part of which are new, have
a much nearer relation to those of India than to the
American portion of the order. Among these there are
several species of Nelsonia[4] and Hypoestes;[5] a new species
of Aetheilema[6] a genus from which perhaps Phaylopsis of
Willdenow is not different, though its fruit is described by
Wendland[7] as a legumen, and by Willdenow, with almost
equal impropriety, as a siliqua; a plant belonging to a
