110 BOTANICAL GAZETTE , [auGUST a 
spirals. This has been described by BarLey (5) for some species of 
Pinus as wall as for Picea and Pseudotsuga. He states: “Ray 
tracheids appear to follow closely the wood tracheids. Where spirals 
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Fic. 13.—P. resinosa: adult stem; a series of tracheids from a wounded region, 
showing transformation to ray tracheids. 
are strongly developed (summer wood) in the latter elements, they 
will also appear in the former.’’ This concomitant occurrence © 
tertiary spirals on the elements in question argues community of 
origin. 
Seedling 
So far the study of the seedling has presented no features not — 
observed in the corresponding regions of the adult, except that here 
the ray tracheids are later in appearing. 
Cone axis 
: ” : 7 
True ray tracheids are quite absent from the cone axis, as J EFFRE 
and CHRYSLER (6) have pointed out. I have found their place taken, : 
however, by the bent ends of the tracheids. Fig. 14 shows a trachelé — 
See ee 
