362 BOTANICAL GAZETTE [MAY 
Discussion.—As stated above, neither axillary nor adventitious 
buds occur in the rhizomes of either Ophioglossum vulgatum or O. 
pendulum; and where branching occurs in these species, it is dichoto- 
mous. On the other hand, the buds and branching of Helmin- 
thostachys resemble those of Boirychium in every respect. These 
facts may be considered further evidence of the close relationship 
of these two genera; at the same time, they will serve to emphasize 
the differences between these two genera on the one hand and 
Ophioglossum on the other. 
LANG (9) has mentioned the similarity between the vascular 
connection of the branches of Botrychium and of species of the 
Hymenophyllaceae. For purposes of comparison, the origin of the 
axillary buds of a species of Trichomanes from Samoa has been 
examined. The leaf has an apical cell from the beginning and 
develops to a considerable extent before the branch appears. The 
formation of the branch is initiated by the appearance of an apical 
cell. The exact method of formation of this apical cell of the 
branch was not determined; but it is evident that it arises late and 
from the growing point of the leaf. The axillary branches of 
Trichomanes, therefore, are foliar in origin. In Botrychium, as 
shown above, the axillary bud is in no way related to the apical 
cell of the leaf; it arises directly from a portion of a segment of the 
apical cell of the rhizome; and its position on the base of the leaf 
is incidental and does not indicate a foliar origin. The similarity 
between the branching of Botrychium and Trichomanes, therefore, 
is not close. 
The mature axillary buds of Botrychium are of the simplest pos- 
sible form, an undifferentiated layer of meristematic cells; and it is 
to be noted that at no time in their development is there any differ- 
entiation. This may be accepted as evidence of reduction produced 
in connection with dormancy; and we may conclude that Botrych- 
ium and Helminthostachys have been derived from a form which 
branched freely in a monopodial fashion. This is in full agreement 
with other evidence which points to a relationship of the Ophio- 
glossaceae to the primitive forms of Filicales, especially the ZygoP- 
terideae. 
