58 



BOTANICAL GAZETTE 



[JANUARY 



Development of flower 



The first evidence of the formation of flowers is the appearance 

 of papillae in the axils of the bracts (fig. iifl); these papillae are 

 the primordia of the receptacles of the flowers. The outline of 

 the receptacle soon becomes angular through the upward growth 

 of four hemispherical protuberances from its distal surface (fig. nb) r 

 and soon afterward its base produces a ring-shaped outgrowth 

 (fig. nc). The former develop into the stamens, and the ring 

 immediately afterward separates into the corolla and the calyx 



16 



Figs. 11-17. — Floral development in V. an git sti folia; X35 



tube (fig. 12). The appearance of the carpels is indicated by a 

 broadening of the receptacle (figs. 12, 13). 



In fig. 13 the calyx tube has begun to curve inward over the 

 top of the flower. Within this the corolla tube, the hemispherical 

 young stamens and the two carpels appear in succession. Their 

 later stages are shown in figs. 14-17. 



Development of megaspore and embryo sac 



When the ovule has reached the stage shown in fig. 15, the sub- 

 epidermal megaspore mother cell that terminates the axial row 

 of the nucellus can readily be distinguished from the surrounding 

 cells through its larger size and large nucleus (fig. 18). The 



