OF CENTRAL AFRICA. 285
parts in question : and I may remark that similar observa- tions on certain genera of Caryopliyl'.eyc, especially Diantluis, Lychnis, and Silene, clearly establish the analogy between their petals and those of Reseda.
I am aware that it lias lately been proposed to include JDafisca in Resedaceoc, to which it is nearly similar in the structure of its ovarium, as M. dc Jussieu has long since remarked. But this is the only point of resemblance be- tween them ; for the calyx of Datisca is certainly adherent, and in most of its other characters it differs widely both from Reseda and from every other genus yet published. Among the nmnerous discoveries made by Dr. Horsfield in Java, there is a genns (Tetrameles nob.), however, mani- festly related to Datisca, and remarkable in the regular quarternary division of every part of its dioecious flowers. These two genera form an order very different from every other yet established, and which may be named Da- TiscE-a;.
CARYOPHYLLEiE. Fivc spccies Only of this family were collected near Tripoli, none of which are new^
Of Zygophylle^e, six species exist in Dr. Oudney's her- barium, namely, Tribulus terrestris, found in I^ornou ; Pagonia cretica, from Tripoli to Benioleed ; Tagonia arabica, at Aghedem ; Fagonia Oudneyi nob. with Zygo- phyllum simplex in Fezzan ; and Zygophyllum album everywhere in the desert.
This family, so distinct in habit from Diosmeae or Rutacese, with which it was formerly united, is not easily characterised by any very obvious or constant pecu- liarities in its parts of fructification.
The distinguishing characters in its vegetation or habit are the leaves being constantly opposite, with lateral or [^31 intermediate stipula?, being generally compound, and always destitute of the pellucid glands, which imiversally exist in true Diosmeic, though not in all Rutacea; pro- perly so called.
M. Adrien de Jussieu, in his late very excellent ^Icmoir on the great order or class Rutacea^, in distinguishing
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