OF CENTRAL AFRICA. 291

fore, exceptions to all the assumed characters of ^Miniosese arc found, and there is some approacli in both genera to the habit of Cirsalpineoc. It is still possible, however, to distinguish, and it will certainly be expedient to preserve, those two tribes or orders. Abandoning divisions strictly natural, and so extensive as the tribes in question, merely because we may not be able to define them with precision, while it would imply, what is far f]'om being the case, that our analysis of their structure is complete, would, at the same time, 1)e fatal to many natural families of plants at present admitted, and among others to tlie universally re- ceived class to which these tribes belong. No clear cha- racter, at least, is pointed out in the late elaborate work of ]M. De Candolle/ by which Legiiminosa3 may be distinguished from Terebintacese and llosaceae, the orders supposed to be most nearly related to it. It is possible, however, that such characters, though hitherto overlooked, may really exist; and T shall endeavour to show that Leguminosae, indepen- dent of the important but minute differences in the original structure and development of its ovulum, niay still be dis- tinguished at least from Ilosacea\

In the character of Poly galeae, which I published in 1814," I marked the relation of the parts of the floral envelo})es to the axis of the spike, or to the subtending bractea. I in- troduced this circumstance chiefly to contrast Polygalea3 with Leguminosae, and to prove, as I conceived, that Secu- ridaca, which had generally been referred to the latter family, really belonged to the former.

M. Dc Jussieu, who soon after published a character of Polygaleac, entirely omitted this consideration, and con- tinued to refer Securidaca to Leguminosa?. M. De Can- dolle, however, in the first volume of his ' Prodromus,' has adopted both the character and limits of Polygalea3, which [236 I had pro])osed, though apparently not altogether satisfied wdth the description he himself has given of the divisions of the calyx and corolla.

The disposition of the parts of the floral envelopes, with

1 Memoires siir la TamUk des Legumincuses.

2 Flinders' s Voy. to Terra Anstr. 2, p. 51-2. (Jtilt',j}p. 13, li.)

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