APOCINEAE. There are only six plants in the collection belonging to this order.
The first of these, together with some other species from Sierra Leone, constitutes an unpublished genus, the fruit of which externally resembles that of Cerbera, but essentially differs from it in its internal structure being polyspermous. The Cream fruit of Sierra Leone, mentioned by Professor Afzelius,[1] probably belongs to this genus, of which an idea may be formed by stating its flower to resemble that of Vahea, figured, but not described by M. Lamarck,[2] and its fruit, that of Voacanga[3] of M. du Petit Thouars, from which birdlime is obtained in Madagascar, or of Urceola[4] of Dr. Roxburgh, the genus that produces the caoutchouc of Sumatra.
The second belongs to a genus discovered in Sierra Leone by Professor Afzelius, who has not yet described it, but has named it Anthocleistia. This genus, however, differs from Potalia of Aublet (the Nicandra of Schreber) solely in having a four-celled berry; that of Potalia being described both by Aublet and Schreber as trilocular, though according to my own observations it is bilocular. M. de Jussieu has appended Potalia to his Gentianeae, partly determined, perhaps, from its being described as herbaceous. The species of Anthocleista from Congo, however, according to the account given me by Mr. Lockhart, the gardener of the expedition, is a tree of considerable size, and its place in the natural method is evidently near Fagraea.
Whether these genera should be united with Apocineae or only placed near them, forming a fifth section of the intermediate tribe already proposed, is somewhat doubtful.
In the perfect hermaphrodite flowers of Apocineae, no exception occurs either to the quinary division of the [450 floral envelopes and corresponding number of stamina, or to the bilocular or double ovarium; and in Asclepiadeae, which are generally referred by authors to the same order, something like a necessary connection may be perceived
