178 Campbell. — On the Development of 
lower, the one next the leaf-quadrant forms the root, the 
other the foot ; so that these organs have the same relative 
positions as in the embryo of the ordinary Ferns. Berggren 1 
states that the root does not arise until later, and is derived 
from the foot ; but in sections it is plainly recognizable from 
the very first, and corresponds in position exactly with that of 
other Ferns. 
In regard to the next walls there is not always absolute 
regularity. In all but the stem-quadrant, the octant-walls 
divide the quadrants into exactly equal parts, and this may 
be true also of the stem-quadrant. In the latter, however, 
(Fig. 64 a), the octant-wall may make an acute angle with 
the quadrant-wall, and the larger cell of the two thus formed 
functions at once as the apical cell of the stem, and divides 
from now on by walls directed alternately right and left. 
When the stem-quadrant is divided into equal cells by the 
octant- wall it is probable, although this was not positively 
proved, that for a time the apical cell of the stem forms three 
sets of segments instead of two. This seems probable from 
the fact that often when seen from the side (see Fig. 71 a), 
two series of segments can be seen, which could hardly be 
true were there but two series cut off from the apical cell. 
The Cotyledon. 
The first divisions of the cotyledon are extremely regular, 
and resemble those in the later leaves. The cotyledon, 
however, as well as the other leaves of the young plant, is not 
divided into the lobes found in the leaves of the older plants. 
Following the median octant-wall, a vertical wall is formed 
in each of the two octant-cells (Fig. 66 b), forming two cells 
that seen in section appear triangular, and two which appear 
to be four-sided. The two former, which have larger nuclei 
than the other cells, divide for some time in much the same 
way that we saw in the formation of the sporocarps in the 
fertile lobes of the sporophylls, and may, perhaps, be equally 
1 loc. cit. p. 4. 
