316 BOTANICAL GAZETTE [APRIL 
the multiseriate rays more numerous and parenchymatous, but 
the ring of growth is wider and the vessels and tracheids correspond- 
ingly larger in the vigorous (figs. 1, 2, 3, 4) than in the non-vigorous 
or suppressed year old twigs (figs. 7, 8). 
SHOOTS FIVE TO NINETEEN YEARS OLD.—In general the three 
types of medullary rays previously described as characteristic of 
the white oak wood occur in all shoots from 5 to 20 years old, but 
there are three distinct types of compound rays: (1) rays which 
