EMBRYOGENESIS IN THE LYCOPODINEAE 



111 



apical cell and that of the first leaf. At this stage the young embryo is a 

 filamentous structure which is being thrust into the nutritive prothallial 

 tissue by the suspensor. In the ensuing development, the embryo 



Fig 26. Embryogeny in Selaginella poulteri 

 A Archegonium, a, with ovum. B, Englarged venter with young embryo showing 

 fir'srtransverse wal C. D, The segmentation of the enlargmg embryo. E, The 

 elongrd embryo .. becomes deeply embedded in the gametophyte but begins to 

 curve round f! An early stage m the organisation of the ^n^^ryo proper; .the 

 apLal cell of the shoot; /, the greatly enlarged foot: su, suspensor, (all x 225, 



after Bruchmann). 



becomes a short, massive, axial body, and begins to grow nriore rapidly 

 on tlie lower side and therefore to curve withm the pro hallus. In due 

 course this process results in the emergence of the embryo as an up- 

 wardly directed shoot. Meanwhile, the morphologically basal region 

 of the convex side has enlarged into a large suctorial foot, the extent ot 

 this developmem varying from species to species (see below). 



