EMBRYOGENESIS IN FLOWERING PLANTS 



279 



of distended cells, sometimes irregularly disposed, and containing many 

 nuclei. These cells are described as having a haustorial function. The 

 upper region of the suspensor, which is derived from a tier of the 

 embryonic region, consists of two tiers of uninucleate cells. These have 



Fig. 74. Various anomalous embryos 



A, B, Sciirrula atropurpurea. A, First division of zygote. B, Enlarged view of distal 

 region of proembryo, showing beginning of elongation of suspensor cells (after 

 Ranch). C, D, Balanophora abbreviata. C, Two-celled embryo resulting from 

 longitudinal division of zygote. D, A more advanced stage (after Zweifel). E-G, 

 Scabiosa succisa. Stages in the development of the embryo (after Soueges). 



a staining reaction similar to the suspensor cells below, but they remain 

 small and uninucleate and project in a foot-like manner into the lower 

 portion of the suspensor, Fig. 75. In some embryos, however, the 

 suspensor remains relatively undeveloped or it may be absent. Both 

 types of suspensor may be observed in the same ovary. The proembryo, 

 at first filamentous, becomes a globular mass, with irregular divisions, 

 and this eventually develops into an elongated, spirally or irregularly 



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