Osmunda claytoniana , Z., and O. cinnamomea , Z. 73 
Of the four quadrants the two epibasal form the stem and 
cotyledon ; the hypobasal the root and foot. At this stage 
the cells of the young embryo (Figs. 80, 81) are nearly trans- 
parent, and the granular contents comparatively scanty and 
confined to the periphery of the cells and the vicinity of the 
nucleus, from whence extend threads and thin plates of granular 
protoplasm. The nuclei are large, and have a well-marked 
nucleolus. As the embryo grows larger the contents of the 
cells become denser. 
The first divisions in all the octants are the same, so that it 
is not possible to say which one in each quadrant is destined 
to be the future apical cell ; but soon the divisions become 
more irregular in one of each pair of octants, and its apical 
cell ceases to be recognizable as such. The first division wall 
in each octant (Figs. 83, 83, 84) runs in a curved direction, so 
that it strikes the basal and quadrant walls, and divides the 
octant into a tetrahedral cell, bounded on its other faces by 
the basal, octant, and outer walls of the embryo ; and a second 
cell bearing the form of the segment of an ordinary tetrahedral 
apical cell, except that it is deeper than usual. Sometimes 
the first wall in the octant, instead of cutting the basal wall, 
strikes the median and octant walls. In either case, the 
embryo at this stage (Figs. 82, 83) consists of sixteen cells, all 
of which have one free outer wall. 
Owing to the difference in the position of the first walls in 
the octants in different instances, the relative position of the 
apical cells varies a good deal, and the position of the organs 
in the older embryo is, of course, influenced by the direction 
of growth in the axis of the organ due to the position of the 
primary apical cells. 
Before the second’segment is cut off from the apical cell of 
each octant, the first segment divides by a periclinal wall into 
an inner and outer cell (Fig. 85, 2). Apparently in the 
octants that are not to form the growing-points of the organs 
of the embryo, no more segments are cut off from the apical 
cell, and the latter is obliterated by the formation of a periclinal 
wall, after which no regular succession of cells can be made 
