150 



NATURAL HISTORY OF PLANTS. 



long-stipitate gynseceum. The sepals are free, one anterior, one 

 posterior, and one on either side. The two latter are covered in the 

 bud by the two former, which are also imbricated ; the posterior is 

 usually covered by the anterior, and differs in being more concave 

 and arched (fig. 176). The four twisted sessile petals, regularly alter- 



Capparis spinosa. 



Fig. 175. 



Long. sect, of flower. 



nating with the sepals, form, however, an irregular corolla, as the 

 two anterior alone have their contiguous lower edges valvate, 

 thickened, greenish, and covered with down. Between these the 

 receptacle swells into a little inverted heart-shaped glandular pro- 

 minence. The indefinite stamens come next on the conical recep- 

 tacle; 1 their filaments are free, corrugated in the bud, with an 

 introrse two-celled anther of longitudinal dehiscence. 2 The 



1 Pater (loc. cit. 205) bas seen that they 

 arise from above downwards on the receptacle; 

 first four stamens, superposed to the sepals ; then, 

 lower down, four others, alternating with these; 

 next eight more, alternating with the former 

 eight; and so on from within outwards. 



2 The pollen consists of ellipsoidal grains, 

 which, when moistened, become spherical, with 

 three papillose bands. This is the case according 

 to H. Mohl (in Ann. Sc. Nat, ser. 2, iii. 327), 

 in C. spinosa, cegyptiaca, tomenlosa, cqfra, 

 cynopli a Uuphora. 



