3 1 2 Bower. — The comparative examination of the 
cases, cells of a pyramidal form have been found occupying 
an approximately central position in median sections : but in 
no single instance has an apical cell been observed having that 
regularity of form, and of the arrangement of its segments, to- 
gether with the central position, which are so characteristic of 
the roots described by Naegeli and Leitgeb. Taking as the 
first example (Fig. 6 ) one of those which approaches most 
nearly to that type, the pyramidal apical cell (x) can be 
readily recognised ; but a comparison with the figures of 
Naegeli and Leitgeb, or with Fig. i, shows certain points of 
difference. In the first place there is a difference in the form 
of the cell itself ; it is in Osmunda proportionately narrower 
and deeper, that is, more elongated in a longitudinal direction, 
and consequently the principal walls by which it is bounded 
laterally are less inclined to the longitudinal axis. Secondly, 
the arrangement of the cells surrounding the pyramidal cell 
does not show any definite regularity, and it is thus difficult 
to ascertain their genetic connections. This irregularity is 
found not only in the tissue adjoining the sides of the pyrami- 
dal cell, but also in those which have been derived from its 
base, and will go to form tissues of the root-cap. This, it 
may be stated, is one of the most regular examples of the 
apex of the root of Osmunda which I have observed. 
A further point to be noted in Fig. 6, as also in Fig. 7, is 
that in point of size the wedge-shaped cell is smaller in com- 
parison with the adjoining cells, than is the case in other 
Ferns : whereas in Naegeli’s figures the area of the apical cell 
equals or exceeds that of any of the surrounding cells, in Os- 
munda it is often smaller than they. In the apex represented 
in Fig. 7, a central pyramidal cell is clearly seen : here, though 
there is no marked ascendancy of the neighbouring cells in 
point of size, still if the genetically connected groups of cells, 
enclosed between the successive anticlinal walls be taken into 
consideration as products of successive segments, it is clear 
that the construction here differs considerably from the ordi- 
nary confocal type ; the ascendancy of the apical cell is less 
marked, and periclinal walls predominate, while the anticlinal 
