3i6 



MOSSES AND FERNS 



CHAP. 



hypobasal. The former produces the stem and cotyledon, the 

 latter the primary root and foot. The early divisions are 

 extremely regular, and offer a marked contrast to those in the 

 eusporangiate embryo. The second wall is the transverse 

 (quadrant) wall, separating the leaf and stem in the epibasal 



A. 



Fig. i6o. — A, Median longitudinal section of a young embryo of Adiantiim co7icinnuin (H. B. K.) 

 (after Atkinson) ; B, a four-celled embryo of O. struthiopteris ; C, an older embryo of the same 

 in nearly median section, X250 ; st, stem ; R, primary root ; L, cotyledon ; F, foot. 



part, and the root and foot in the hypobasal. The next walls 

 are the median or octant walls, but they do not correspond 

 exactly in all the quadrants. While in the cotyledon and stem 

 they are almost exactly median, in the root especially the 

 octant wall diverges often a good deal from the median line. 



