EMBRYOGENESIS IN FLOWERING PLANTS 



247 



The herbaceous and woody Rosaceae show considerable differences 

 in their embryological characters. Ahhough the herbaceous Rosaceae 

 show a considerable range in their floral morphology, they exhibit a 

 remarkable similarity in their embryology. That of Geum urbanum. 



Fig. 61. Dicotyledon embryos as in Fig. 60 



A, Poterium sanguisorba (x 250). B-D, Crataegus oxyacantha (x 340). E, Mains 

 communis (x 450). F-H, Saxifraga caespitosa (x 235). J, S. cotyledon (x 340). 

 K-N, Peltiphyllumpeltatum{K-M, x 340; N, x 270). O-Q, Penthorum sedoides 



(x 410) (after Lebegue). 



Fig. 56l, m, may be taken as typical. The apical, or terminal, cell of 

 the two-celled proembryo gives rise to the cotyledons and epicotyl 

 only, all the rest of the embryo, including the hypocotyl, root, root-cap 

 and suspensor, being products of the basal cell. In these species of 

 Rosaceae, the terminal cell is divided by a first and then a second oblique 

 wall, a distinctive apical cell, apical cell group or epiphysis, being thus 



