1915] PETRY—OPHIOGLOSSACEAE 350 
two growing points were doubtless established. This produced a 
physiological demand which, operating under the conditioning 
factors just described, produced two branch steles. 
The conclusion that is reached, therefore, is that the vascular 
connections of the branches are determined in general by three 
factors. These factors are (1) the presence of stelar tissues capable 
of growth within the range of the influence of the developing 
branch; (2) the nature of the growth which can be induced in those 
tissues, in particular, whether such growth is cambial or not; 
(3) the physiological demand produced by the growing branch. 
The first of these factors will vary with the distance of the bud from 
the leaf trace as compared with its distance from the stem stele; 
and, more particularly, with the age of those structures when the 
branch begins to develop. The second factor may be considered 
to be relatively constant for any one species but to vary widely 
with different species. The vascular connection produced is the 
direct result of the third factor acting upon and limited by the 
other two; the individual conditions give to this third factor a 
special value for each particular case; the resultant structures are 
therefore direct responses to unknown and varying conditions and 
of physiological interest only. It is therefore concluded that the 
vascular connections of the branches of Botrychium have little or 
no phylogenetic significance. 
THE ORIGIN AND DEVELOPMENT OF THE AXILLARY BUDS 
In view of the foregoing conclusion, attention has been turned 
from the anatomy of the branch connections to the examination of 
the origin of the axillary buds. Since Lanc’s description of these 
buds in B. Lunaria deals only with the mature structures, the further 
investigation has been directed toward the examination of the 
origin and development of these buds in B. obliquum. 
The apical region.—The apical region of Botrychium has been 
described in detail by Hotte (6), CAMPBELL (3), and BRUCHMANN 
(2). All agree that growth takes place by means of an apical cell 
of the form of a triangular pyramid, and that each segment of the 
apical cell probably gives rise to a leaf. BRUCHMANN states that 
in B. Lunaria leaf formation begins by the appearance of an apical 
