A TRIBE OF LEGUMINOSJAX. 15 
been able to do for the convenience of study is, to distribute them 
into five series founded on the form and venation of the leaflets, 
and partaking of all the uncertainty and indefiniteness usually 
attending on characters of that kind. 
Drepanocarpus, united by Linnsus with Pterocarpus, is, when 
in flower, precisely the same as Macherium, and several of the 
species assume several of the different types of foliage observed in 
that genus. The fruit is also formed upon the same plan, although 
it is at first sight so different in shape that the two have seldom, if 
ever, been brought into comparison. The differences, however, 
consist only, first, in the indenture on one edge opposite the seed 
being much deeper, and the corresponding curvature of the oppo- 
site edge much greater, giving the pod a reniform or circinate 
shape, instead of being nearly straight; and secondly, in the 
upper end of the pod being not at all or scarcely perceptibly 
attenuated into a wing. They are, therefore, differences in degree 
and not in plan, and I should have united the two genera as 
artificial sections of one, were it not that, as with Ecastaphyllum, 
Drepanocarpus is an old-established and universally adopted genus, 
recognizable by a tolerably positive, though purely artificial cha- 
racter. The only tendency towards an intermediate form of pod 
among known species may be traced through Macherium Moritz- 
lanum, M. leucophyllum, and Drepanocarpus cristacastrensis. 
TIPUANA, PLATYPODIUM, CENTROLOBIUM, and PTEROCARPUS. 
These four small genera, each with its own peculiar habit and 
characters, have all several points in common. The pod, as in 
Macherium, is more or less samaroid, indehiscent, and flattened, 
thickened round the seed, and tending to expand in one direction 
or another into a wing. It is usually one-seeded, as in Macherium ; 
sometimes, however, two, or even three seeds will ripen. They are 
then not distant, and separated by a thinner or contracted part of 
the pod, as in Dalbergia or Lonchocarpus, but close together in the 
thickened part, separated only by thin but hard or woody trans- 
verse partitions. The flowers are usually larger than in Mache- 
rium, often yellow, and the inflorescence looser, the calyx (except 
ш Centrolobium) turbinate or narrowed at the base, the narrow 
Part lined with the petal-bearing disk, whilst in Macherium the 
calyx is almost always rounded at the base, with the disk very 
short. The petals are always glabrous, and often waved or crisped 
on the edges, the wings free, the staminal sheath slit open on the 
upper side, and the anthers versatile. The species of the four genera 
