SMITHSONIAN MISCELLANEOUS COLLECTIONS 



VOL. 140, NO. 1, PLATE 13 



TTC ??-/.?-</. Branch section of Citprcssiis arisoiiica, cut January i, I943- 

 Xylem of 1938-1942. Lensing simple, exterior, compound, and overlapping; 

 multiplicity ; growth rhythms. 

 1938: dee; see. 



1939: Frost connected msce ; dL ; see; outer thin see. 

 1940: Growth rhythms (1938-41); dL ; see; sL. 

 1941 : see; ddw as incipient lens. 

 1942: see; compound and overlapping lens of 4 members. 



