28 NATURAL HISTORY OF PLANTS. 
gascar, with bipinnate setaceous leaves possessing a glanduliferous 
rachis and two lateral stipules. The flowers are collected into cylin- 
drical spikes, solitary or fascicled in the axils of the leaves, or of the 
bracts that take the place of leaves at the ends of the branches. 
Prosopis, with the flower of the preceding genera, and especially 
of Piptadenia, has indehiscent fruits like Gagnebina, but they are 
wingless, and vary greatly in general form. ‘The pericarp is always 
coriaceous, with a thick, spongy or suberous mesocarp, and a carti- 
laginous or papery endocarp, continuous with the septa between 
the seeds, and even forming a sort of stone of variable thickness 
round each. In the species of the section Anonychium® the pod is 
straight, hard, and very thick. In <Adenopis* it is 
(icombcsopss cylindroidal, elongated, torulose,* or irregularly 
strombulifera. thickened or distorted. The fruit of Algarobia’ is 
elongated, straight, or bowed, cylindrical or com- 
pressed, narrower between the seeds, and hence mo- 
niliform. The pod of Circiaaria’ is not only bowed, 
but twisted more or less into a spiral; and as its turns 
are not all quite in one and the same plane, this fruit 
affords a transition to Strombocarpus,’ which is rolled 
up like a corkscrew, either loosely and irregularly, or 
very regularly (fig. 21) and with the turns of its 
spiral in very close contact. Thus constituted, the 
genus Prosopis contains some fifteen species’ from all 
tropical and subtropical regions. They are naked 
or spiny trees or shrubs, with stipulate or exstipulate 
leaves, whose petioles may or may not possess glands. 
The flowers, usually axillary, form spikes, cylindrical, or more rarely 
globular or ovoidal. 
Fie, 21. 
Fruit. 
11, Mantiss., n. 1260.—J., Gen. 348.— 
K., Mimos., 106.—DC., Prodr., ii. 446.—EnDL., 
Gen., n. 6821.—B. H., Gen., 591, n. 382.— 
Outv., Fl. Trop. Afr. ii. 331. 
2 Bentu., Gen., loc. cit., 2, This section in- 
cludes two African species, with velvety ovaries 
and internally glabrous petals. 
3 DC., Prodr., sect. 1.—Lagonychiwm Bizs., 
Fi, Taur.-Cauc., iii. 288.—DC., Prodr., ii, 448.— 
Dewsss., Ic. select., iii. 42, t. '75.—iinpb., Gen., 
n. 6822. The petals are also glabrous internally, 
but the ovary is glabrous as well, the branches 
are often covered with scattered prickles. 
4 As in P. spicigera L. (Mantiss., 68,) an 
Indian species (BURM., Ind., t. 25, fig. 3.— 
Roxs., Pl, Corémand., t. 63). 
* In a second species from Western Asia, 
P. Stephaniana (Lagonych Stephanianum, 
Bies., op. ctt., 288;—Acacia Stephaniana, 
BIzs., op. cit., ii. 449). 
6 Beytu., Pl. Hartweg., 13.—Torr. & Gr., 
in Ann, Lyc. New York, ii. t. 12; Fl. N. Amer. 
399.—K., Mimos., t. 33, 34—DC., Prodr., 
sect. ii.—ENDL., Gen., n. 6823. 
7 B.H., Gen., loc. cit, 4. This section has 
only a single species from tropical Africa. 
8 A. Gray, Pl. Lindheym., i. 35.—Torr., in 
Frem. Rep., t. 1.—BENtH., Gen., loc. cit., 5.— 
Watp., Ann, iv. 614. This section is made up of 
five American species. 
9 Watp., Rep., i. 861; x. 582; Ann., i, 259. 
