SPERMATOPHYTES : ANG10SPERMS 



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, 321). When they reach 

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

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

 These are generally called " pollen-sacs," and each anther is 

 said to consist of two pollen-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. 



D 



Fig. 332. Various forms of stamens: A, from Solarium, showing dehiscence by 

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

 "horns"; C, from Berberig; D, from AtJurosperma, showing dehiscence by 

 nplifted valves; E, from Aqvikgia, showing longitudinal dehiscence; F, from 

 Popowia. showing pollen-sacs near the middle of the stamen. — After Engleb. 

 and Frantl. 



