78 NATURAL HISTORY OF PLANTS. 
Cesalpinia; the sepals are valvate or nearly so,' instead of being 
decidedly imbricated, and the anterior sepal is no larger than the 
rest, instead of enveloping them, as in the preceding genera. The 
fruit is a compressed, membranous, coriaceous, bivalve pod, with 
albuminous seeds. The habit is quite different, for the three or 
four species of this genus, from the warm and temperate parts of 
America? are trees or shrubs with knotted or twisted branches, 
axillary spinescent twigs, and bipinnate leaves, with the pinnules 
and leaflets few and small. The flowers form short lax racemes, 
often grouped in small numbers at the projecting nodes of the fallen 
leaves. 
Mezoneurun? has the perianth and androceum of Cesalpinia; but 
the flowers are far more irregular,‘ owing to the deformity of the 
receptacle.’ This assumes an unequal development, so that its rim 
is very oblique, the mouth tapering like a beak towards the posterior 
petal and the placenta. ‘The ovary resembles that of Cesalpinia, and 
contains two seeds and upwards. The fruit is flattened, membranous 
and coriaceous, indehiscent or nearly so, and has its placentary edge 
dilated all the way up into a wing which is flattened out towards 
the free border. The seeds vary in number and resemble those of 
Cesalpinia. The genus Mezoneurum consists of trees or climbing 
shrubs from tropical Asia and Africa, and Australia,’ with bipinnate 
leaves, and the flowers in axillary or terminal racemes. 
The flower is on the contrary, much more regular in Hematowylon' 
(figs. 49-51), as regards receptacle, corolla and androceum. The 
calyx alone has still the anterior sepal larger than the rest which it 
envelopes; all the sepals become reflexed on anthesis. The petals 
are nearly similar to one another, and are imbricated as in Cesalpinia. 
The receptacle is lined with glandular tissue ; in the bottom of it is 
inserted the gynzeceum, consisting of a shortly stipitate ovary, sur- 
1 The edges are as it were bevelled, and touch 
obliquely ; or else the inner sheet of the sepal 
alone projects beyond its edge on the side where 
it should be overlapped in the bud. 
2 Watp., Rep., v. 552; Ann., iv. 594 (besides 
Cesalpinia? cassioides W., Enum., 444). 
5 Desr., in Mém. Mus., iv. 245, t. 10, 11.— 
DC., Prodr., ii. 484.—Enpz., Gen. n. 6768 
(Mezonewron).—B. H., Gen., 565, n. 807. 
4 The vexillary petal may not only differ from 
the rest in form and size, but also bear an in- 
ternal appendage on the base of the limb, analo- 
gous to what is found in certain Sapindacee 
and Erythroxylacee. 
> Inthesection Tubicalyx (Miq., Fl.Ind.-Bat., 
i, p. 1, 1081), this part of the flower forms an 
elongated tube. 
6 Benru., Fl. Austral., ii. 278.—H. By., in 
Adansonia, vi, 196.—Watr., Rep., i. 811.— 
Ann., iv. 590.—Outiv., Fl, Trop. Afr., ii. 260. 
7 L., Gen. n. 525.—J., Gen. 348.—Lamx., 
Dict., i. 591; Suppl., i. 654; Ill, t. 340.—DC., 
Prodr,, ii. 485.—Spacu, Suit. & Buffon, i. 
106.—Env1., Gen., n. 6777.—B. H., Gen., 567, 
u. 310. 
