96 



NATURAL HISTORY OF PLANTS. 



Heterostemon (figs. 68, 69) has nearly the flowers of Palovea 1 and 

 Elisabetha ; 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 Elisabetha, three being greatly de- 

 veloped, and six short and sterile, or reduced to mere filaments. 



Heterostemon mimosoides. 



Fig. 68. 

 Flower (f ). 



Fig. 69. 

 Longitudinal section of flower. 



But they are united into a sort of sheath open towards the vexillary 

 petal. The gynseceum, 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 Humboldtia, and have 

 two bractlets to form a sheath, as in Elisabetha ; but this sheath is 

 very short, revealing almost the whole of the flower. 



1 Desf., in Mem. Mus., iv. 248, t. 12.— DC, Prodr., ii. 488.— Exdl., Gen., n. fi794.— B. H., 

 Gen., 578, n. 338. 



