SPEKMATdl'IlYTES : ANGir>SPERMS 



.361 



If a young anther be sectioned transversely four sporan- 

 gia will be found imbedded beneath the epidermis, a pair 

 on each side of the axis (Figs. 320, 3'31). When tliey reach 

 maturity, the paired sporangia on each side usually merge to- 

 gether, forming two spore-containing cavities (Fig. 321, B). 

 These are generally called " i^ollen-sacs," and each anther is 

 said to consist of two piollen-sacs, although each sac is made 

 up of two merged sporangia, and is not the equivalent of the 

 pollen-sac in Gymnosperms, which is a single sporangium. 



B 



Fig. 333. Various forms of stamens: A, from, Solanum. showing dehiscence by 

 terminal pores; B, from Arbutus, showing anthers with terminal pores and 

 "liorns"; C. from Berberis : D. from Ath(rosp>;rma, showin.s: dehiscence by 

 uplifted valves; E, from Aqmkgla, showing longitudinal dehiscence; F, from 

 Fnpoichi. showiiic; pollen-sacs near the middle of the stamen,— After Englek 

 and Pkantl. 



