Bulletin No. 13, Division of Forestry. 



Plate XXVI. 



m.r: 



r.d.- 



in.rr 



-in.r. 



■ I -Vr.d 



lA 



E 



-p. 



C 



-r.d 



Tangential Sections of Pinus echinata, heterophylla, and glabra, showing Number and Distribution of 



Pith Ravs and Proportion of Pith-ray Cells. 



