Notes. 
485 
archegonium. The next division is parallel with the long axis of 
the prothallium, and at right angles to the first. The third cross-wall 
is in the transverse direction of the prothallium, and at right angles 
to the other two. I have been unable to follow satisfactorily the 
subsequent divisions. The organs appear very late, and only after * 
the embryo has attained a large size. The root is the first of them 
to emerge, and the proliferation of the cells, indicating its place of 
origin, is long unmarked by the presence of an apical cell. The 
cotyledon, stem-apex, and the foot, appear nearly simultaneously. 
The root and cotyledon originate from the upper part of the em- 
bryonic mass ; the foot and stern-apex from its lower cells. The 
apex of the root in many cases is in the same straight line with the 
canal of the archegonium-neck. 
It seems hardly possible to derive the organs from definite octants 
of the embryo. 
The growth of the root ruptures the calyptra, and its exit is 
followed somewhat later by that of the cotyledon. The latter is not 
a bilaterally symmetrical structure, as in most Ferns, but is of the 
same palmate type as is found in the Osmundaceae. The cotyledon 
begins to assimilate as soon as it reaches the surface of the ground, 
and thus resembles that of Ophioglossum pedunculomm. 
There seems to be no evidence to indicate that more than the 
cotyledon appears above ground in the first season of the young 
plant’s growth. In following summers apparently only a single leaf 
is produced, as is the case with the older plant. I have found young 
sporophytes, bearing their sixth leaf, still attached to the mother- 
prothallium; and as I have never found more than one leaf on the 
young spore-plants at once, and as the leaves, like other organs of 
this species of Botrychium , are extremely resistant to decay, I am 
reasonably certain that such examples were in the sixth year of their 
existence. This longevity of the gametophyte is of some interest. 
One frequently finds two or more sporophytes on a single pro- 
thallium, and in many of these cases the apex of the prothallium 
is bifurcated. In one case I found two spore-plants which had arisen 
from a single embryo. In another case I discovered two tracheids 
in a prothallium in the vicinity of a decayed young spore-plant. The 
latter may have been of apogamous origin, as a similar phenomenon 
generally accompanies apogamy. I have not yet studied thoroughly 
the growing region of the prothallium, as it is best examined in 
