H. Ltoe. 181. 



PLATE XXIV. 



m.i 



G 



E 



j 



H 



TANGENTIAL SECTIONS OF PINUS T/EDA, HETEROPHYLLA, AND QLABRA. 



A, PINUS i HETEROPHYLLA. Radial and tangential sections of a transverse resin duet; r. tl . resin duct; MI. r. medullary ray; tr., tracheids of 



_ tne m edullary ray; p., parenchyma cells of the same; c. tr., common tracheids or wo d fibers. 

 -Cr, PINUS OLABRA. , tangential section of a transverse resin duct and parts of three fibers; 6. .. bordered pit; other lelters as above; 



C-W, tangential sections of niedullary rays, of which K is made up of tracheids only, while /> is a "triple' 1 ray. 

 H, PINUS T^EDA. Tangential sections of medullary rays in spring and summer wood. 



Original magnified "1", illustrations about }. 



