Botrychium simplex , Hitchcock. 
449 
Bruchmann’s figures of such intermediate stages in B. lunaria do not 
show any evident root-initial, which is first shown in much older embryos. 
In corresponding stages of both B. obliquum and B. virginianuni the writer 
has found the initial cell of the primary root to be readily demonstrable. 
In the former species, however, the initial cell is developed later than in 
B. virginianuni , and origi- 
nates near the centre of 
the embryo, very much as 
in the Marattiaceae and 
Ophioglossum . In B. vir- 
ginianum the root-initial 
is cut off from a superficial 
cell, much as in the lepto- 
sporangiate ferns. It is, in 
fact, very much like the cell 
r shown in Text-fig. 5. 
The large embryo 
shown in Text-fig. 6 ap- 
pears to be somewhat 
younger than Bruchmann’s 
Fig. 42, but it shows 
decidedly more differen- 
tiation of the parts than 
Bruchmann’s figures of B. 
lunaria exhibit. In the 
latter, apparently the only 
sign of differentiation in the 
embryo at this time is the 
presence in the axis of what 
looks like the beginning of 
a strand of procambium. 
The apex of the root seems 
to be quite undifferentiated. 
In B. simplex , at this 
stage, the apical cell of the 
root, r, is clearly evident, and the apex of the embryo is occupied by a group 
of columnar meristem cells, one of which is probably the initial for the 
stem-apex, and possibly one may represent the apex of the cotyledon ; but 
it is not possible to be sure of this. There is a slight indication of the 
formation of an axial procambium strand, but, unlike B. lunaria and 
B. virginianum , the foot, as such, is not clearly delimited, and the embryo 
at this stage suggests the bipolar embryo of B. obliquum. 
The writer was unable to secure any stages between this embryo and 
B 
Text-fig. 6. a. Nearly median section of a large 
embryo showing the initial of the root, r, and the apical 
meristem. x 300. b. The apical meristem from another sec- 
tion of the same embryo. 
