49 BOTANICAL GAZETTE [JULY 
stages in the development of the xylem portion of such a ray have 
been observed in numerous instances, and one is represented in 
fig. 4, from a 7-year root of P. aristata. It will be seen that the 
narrow ray ends on the xylem side in a somewhat pointed cell. 
This method of formation of a narrow ray differs from the one 
described by THompson in that the initial activity seems here to be 
on the phloem side, and the narrow ray is wholly independent of 
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Fic. 4 
Fics. 3, 4.—Fig. 3, P. resinosa, 
ray; X275; fig. 4, P. aristata, 7 
ray; X275. 
5-year root: radial plate giving rise to a narrow 
-year root: beginning of the production of a narrow 
eet oarliae mes a. the xylem side. Instead of giving rise to a 
narrow rays | radial group may be lined up with two or three 
cells. We have ca ve consist at first wholly of tracheidal 
in the young roo a a prolific source of new, that is, secondary rays 
tous : A Mave observed the formation of parenchyma- 
“ps in the same manner in J uni perus. 
takes — om the same _— as fig. 3, is seen what frequently 
men one of the radial groups adjoins a medullary ray- 


