416 



NATURAL HISTORY OF PLANTS. 



to Picrcena and Simaruba, but characterized by a thick disk, stamens 

 covered with hairs, and albuminous seeds, while Picrana has a 3-5- 

 lobed disk, stamens naked and glabrous, petals non-accrescent after 

 anthesis, and exalbuminous seeds like those of Quassia. Picrolemma, 



Picrcena excelsa. 



Fig. 472. 

 Female fioriferous branch (A). 



a small Brazilian shrub, with imparipinnate leaves, tetramerons, 

 dioecious flowers, with four imbricated petals, the same number of 

 superposed stamens, and a disk thick and elevated in the female 

 flowers, wanting in the male. Brucea (fig. 473), whose tetramerous, 



tures alternately prominent within and without, 

 five sepals, imbricated petals, two verticils of 

 five stamens, with introrse slightly oscillating an- 

 thers. At the bottom of the receptacle are two 

 free carpels with obconical support, upon which 

 is articulated a one-celled ovary with almost 

 gynobasic style. On the internal wall of the 

 ovary two collateral-dcscendont anatropous ovules 

 are inserted with superior exterior inicropyle 



capped by an obturator. Rigiostachys, whose 

 fruit is unknown, is a Mexican tree (?) with 

 alternate, stipulate, imparipinnate leaves, not 

 bitter, and very numerous tlowers united into a 

 large ramified raceme, the tertiary divisions of 

 which bear alternate bracts and pedicellate arti- 

 culate flowers, accompanied by two lateral 

 bractlets. (See Adansonia, x. 42). 



