2 4 8 



PLANT /.//■/■:. 



pollen spores sift out through the pore so formed (fig. 264) ; 

 or (2) a crack begins at one point and extends lengthwise of 

 the sporangium, in which case the anther is said to open by 

 slits (figs. 259, 260, 261) ; or (3) the break occurs along a 

 line considerably curved, and the flap (valve) thus loosened 

 curls up or lifts so as to allow the escape of the spores (fig. 

 265). All three methods are dependent upon some special 



Fig. 265. 



Fie. 264. — Anther and pollen of a Rhododendron. A, the anther, opening by pores at 

 the end and allowing the pollen to escape. Magnified 8 diam. //.pollen grains ad- 

 herent in four-, (tetrads) as formed in the mother tells: the tetrads an- held together by 

 a stirkv material which draws nut i 1 1 1 . . cobwebby threads as they are separated. Mag- 

 nified 50 diam. — After Kernel 



FlG. 205. A flower oi cinnamon, halved. The calyx and stamens are raised on a cup 

 developed around the pistil. The anthers open bj uplifted valves, one for each spo- 

 rangium, which lure are arranged in two stories instead of in pairs side by side. Mag- 



nilied about 7 diam. — After 1. 



structure of the wall of the sporangium at the lines of rup- 

 ture. 



349. Union. — The stamens are not infrequently united 

 with each other or with some of the neighboring leaves of 

 the flower. They may l>e united to ea< h other by their fila- 



