1922] BLOMQUIST—ANGIOPTERIS 195 
the root appearing on the central strand was related to the next 
leaf above, while the one attached to the commissural strand 
corresponds to the leaf trace above that. The appearance of roots 
on the commissural strand seems to be a common occurrence in 
the older stems. 
VASCULAR ANATOMY OF STIPULES 
As has already been mentioned, no conspicuous stipules appear 
until the fourth leaf. At this stage the leaf trace passes through — 
the stipules as a single strand, to which two weakly developed 
xylem strands are attached, which pass to the stipular lobes. In 
the fifth leaf these strands are better developed, and the leaf trace. 
shows signs of forking where the stipular strands are attached. 
The latter remain unbranched for some distance from the leaf 
trace, when each gives off usually two branches to the upper part 
of the lobes. In the sixth leaf the trace forks where the stipular 
strands are given off, but anastomosing takes place immediately 
beyond. In the seventh leaf the point of forking of the leaf trace 
has moved closer to the stem, and anastomosing is delayed longer 
than in the previous stage. Further branching has taken place in 
the stipular strands. In the subsequent leaves the point of forking 
of the leaf trace moves closer and closer to the central region, until 
finally this takes place as the leaf trace is preparing to free itself 
from the central strand. Likewise, the point of anastomosing of 
the branches is moved farther and farther away from the point of 
* attachment of the stipular strands, until the leaf trace passes into 
the petiole still divided. Above the tenth leaf the two branches 
from the forked leaf trace bifurcate, so that four strands enter the 
stipular region. In this region further branching and anastomosing 
take place. The course of the vascular bundles above the tenth 
leaf is represented in the reconstruction in fig. 34. 
The stipular strands which pass to the lobes of the stipule 
bend outward and pass to within a short distance of the epidermis, 
where they end blindly. The lowest (or the main strand), however, 
is terminated by a procambial strand which originates from a group 
of meristematic cells on the inner side of the edge of the stipule 
slightly above where this merges with the cortex. This meriste- 
