1917] BRUSH—SYCAMORE WOODS 
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Fic. 1.—A, vessel segment of P. occiden- 
talis with se perforations (~) at both ends, 
one at lower end with single bar (); 9, bor- 
dered pits; sp, simple pits; <150; B, end o 
vessel segment of P. occidentalis, Shows sca- 
starm (laddsst¢ 
(ladder 150; 
C, portion of vessel wall of P. Sgeelaieles 
enlarged to show bordered pits on upper surface (a) and in profile 
(6); X400; D, intermediate form between vessel and tracheid from 
wood of P. occidentalis, showing simple perforation at lower end () 
and scalariform perforations at upper = (scp); bp, bordered pits; 
SP, simple pits; 5k — oblique sim; 
le pits; X150; £, tracheid 
of P. Wrightii with slitlike perforations se both ends (s/p); sp, 8imple E 
pits; Xr150. 
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