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 



SCALE DIVISIONS' 



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 



