LEGUMINOSA-MIMOSEZ. 25 
proper, while the flowers are in globular heads. Altogether about thirty 
species of Piptadenia are known ;’ with the exception of two doubtful 
species from tropical Africa,’ they are all natives of tropical America. 
They are trees or shrubs, naked or covered with prickles, with bipin- 
nate leaves whose petiole and rachis are almost always glandular. 
In habit and inflorescence Plathymenia® is very like Stryphno- 
dendron, or the racemose species of Piptadenia. Its flowers are alto- 
gether those of the former genus in perianth,‘ androceum, and stipi- 
tate ovary, down to the disk internal to the androceum. But the fruit 
differs from that of Piptadenia, Hlephantorrhiza, and Entada, though 
possessing features of each. ‘Thus the cavity of the pericarp is 
single, and its exocarp® splits along the sutures into two valves, as 
in Piptadenia. But, as in Hephantorrhiza, this separates from the 
endocarp ; which last divides transversely, as in Hntada, into as many 
indehiscent joints as there are seeds. These resemble those of 
Stryphnodendron, and are attached by long slender funicles. This 
genus is Brazilian, comprising two species,’ shrubs, with bipinnate 
leaves whose petiole and rachis are usually glandular. 
In Xylia; as in the section Mopa of Piptadenia, the flowers are 
arranged in pedunculate globular capitula, either solitary axillary, 
or collected into terminal racemes. Each flower, often hermaphro- 
dite, pentamerous or tetramerous, is sessile in the axil of a bract. Its 
receptacle forms a little cornet, on whose rim are inserted a gamo- 
sepalous calyx with four or five valvate teeth, a corolla whose petals 
are also valvate and free, or slightly coherent at the base, and eight 
or ten stamens arranged in two whorls, with free filaments and in- 
trorse two-celled anthers, each surmounted by a little stipitate gland 
which falls very early... The gynzceum is the same as in Adenan- 
thera. The fruit is a thick, woody, compressed, sickle-shaped, sessile, 
bivalve pod, with false dissepiments interposed between the obovate 
1 Vettoz., Fl. Flumin., xi. t. 6, 16, 40.— 
K., Mimos., t. 25, 830.—Watp., Rep., i. 858; v. 
578 ; Ann., ii. 450. 
2 Hook. F., Niger, 330.—H. By., in Adan- 
sonia, vi. 211.—O tv., Fl. Trop. Afr, ti. 328. 
3 Benrn., in Hook. Journ., iv. 333.—B. H., 
Gen., 589, n. 375.—Chrysoxylon Casan., Nov. 
Stirp. Decad., 59. 
4 The upper part of the corolla is sometimes 
slightly imbricated. 
5 We use this word for shortness to designate 
the epicarp and mesocarp together. 
° Vetioz., Fl. Flumin., iv. t. 72, ex Casar. 
(?).—Watp., Rep., i. 858. 
7 Benru., in Hook. Journ., iv. 417.—B. H., 
Gen., 594, n. 390. 
8 The existence of this gland has been over- 
looked, so that Xylia, which possesses the in- 
florescence of Leucena has been hitherto placed 
near it; but yet, despite the slight value of such 
a character, if we use it to distinguish ddenxan- 
theree, and absolutely refuse it to Humimosee, 
Xylia must perforce be intercalated in the series 
under consideration. 
