June, 1915.] 
Ray Pits of Conifers. 
543 
ray tracheids are the ray parenchyma cells with semi-bordered 
pits (s. b. p.) upon their lateral walls and simple pits upon their 
end walls (e. w.). These cells make up the storage tissue of the 
ray, in which the products of assimilation are conducted and stored. 
Still more complex in structure and function are the rays which 
i . ■—i >3 
SCALE DIVISIONS- i*5 mm 
Fig. 1. 
Fig. 1. Tangential view Pinus monticola, showing arrangement of the 
rays with reference to the tracheids. 
f. fusiform ray with resin duct. u. uniseriate rays. 
have, in addition to the above tissues, a third tissue designed 
for the secretion, conduction, and storage of resin. A very 
intimate connection of the rays with the vital activities of the 
wood may be inferred from the fact that the rays continue living 
for fifteen years or more, or probably as long as the wood performs 
