96: NATURAL HISTORY OF PLANTS. 
Heterostemon (figs. 68, 69) has nearly the flowers of Palovea' and 
Hlisabetha ; the same receptacle and the same calyx, with a corolla 
of five petals, of which the three posterior are alone well developed. 
The stamens too resemble those of Hiisabetha, three being greatly de- 
veloped, and six short and sterile, or reduced to mere filaments. 
Heterostemon mimosoides. 
Fra. 68. Fig. 69. 
Flower (2). Longitudinal section of flower. 
But they are united into a sort of sheath open towards the vexillary 
petal. The gyneceum, fruit, and seeds are as in the two preceding 
genera. The five or six known species are unarmed trees or shrubs 
from tropical America. Their leaves are alternately paripinnate or 
imparipinnate, or unifoliolate, and the stipules are caducous. The 
flowers form terminal or lateral racemes, as in Hymboldtia, and have 
two bractlets to form a sheath, as in Zisabetha; but this sheath is 
very short, revealing almost the whole of the flower. 
1 DesF., in Mém. Mus., iv. 248, t. 12.—DC., Prodr., ii, 488—Enp3., Gen., n. 6794.—B., H., 
Gen., 578, 0, 338. 
