1922] BLOMQUIST—ANGIOPTERIS 193 
root junction (fig. 14). In these stages the leaf trace bifurcates 
while still within the cortex. 
TENTH AND SUBSEQUENT STAGES 
The tenth stage is very similar to the eighth and ninth, except 
that the different strands have increased in size. In cross-section 
the crescent shape of the central strand is less evident, especially 
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Bs 
Fic. 6.—Diagram of section of stem above tenth leaf stage: c, central strand; 
ms, medullary strand; cs, commissural strand; /t, leaf trace; ss, stipular strands; ps, 
petiolar strands; 7, root; mr, meristematic region of stipule; 8. 
in the region of a root junction. In some places the commissural 
strand and the central strand are very similar both in size and shape. 
The central and the commissural strands and the leaf traces are 
always endarch, while the medullary strand is exarch (figs. 21, 22). 
The commissural strand comes off close to the central strand, and 
the leaf trace bifucates close to the central region. At this and 
the subsequent stages five vascular strands may leave the central 
strand approximately on the same level; namely, the eighth leaf 
