CONIFERALES 



349 



^-■t 



^ 



338). While more than one, and often many, begin to develop, the 

 ripe seed usually has only one which 

 has developed suflEiciently to pro- 

 duce a seedling. 



More than one embryo may orig- 

 inate in different ways. More than 

 one egg in a gametophyte may be 

 fertilized and one embryo may de- 

 velop to a considerable extent from 

 each fertilized egg. This is simple 

 polyembryony. When more than one 



Fig. 337. — Cephalota.xtis Jortunei: A, 

 proembryo, still within the egg, showing 

 the rosette, suspensor (5), embryo, and 

 protective cap: B, later stage, after break- 

 ing through the base of the egg; X63.-~ 

 After Strasburger.^ 



s 



e, 



Fig. T,2,?>.—Piniis banksiana: cleavage 

 polyembryony: s, primary suspensor; e,, 

 62, Ci, first, second, and third secondary 

 suspensor cells (embryonal tubes) ; r, ro- 

 sette; p, basal plate above rosette formed 

 from disorganized remains of egg; X 100. — • 

 After BucHHOLZ.^* 



