154 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I40 



Other specimens. And such supposed omission of growth layers 

 would merit the conclusion that the cambium had lain dormant for 

 more than a calendar year. Our studies indicate, however, that the 

 cambium w'as sluggish, very sluggish, but not dormant for such a 

 long interval. As a matter of fact, the cambium varies in its activity 

 among different branches of TTP 23 ; in some it was very active, in 

 others it was sluggish. The variable activity applies longitudinally on 

 any one branch, as on TTP 23-4, and also around the circuit of any 

 one section. 



The branches TTP 23-5 to 23-20, measured for two years and cut 

 November 11, 1944, are rather simple compared with TTP 20, for 

 instance, and resemble each other to a remarkable degree. With one 

 exception, 1943 contains one growth layer whereas 1944 is almost 

 universally multiple. The intra-annuals of 1944 invariably fade and 

 weaken outward on the branch. In all instances, each year contains 

 one tip flush, except in TTP 23-9. 



Table Sg.—TTP 23-9 



1943 

 1944 



One diameter flush represents two tip flushes in 1943 for TTP 23-9 

 (table 89). The growth layer at 4.3 cm. in 1943 has a feeble and 

 weak outer contact. 



Branches TTP 24-1 to 24-4 were cut from the tree November 29, 

 1941. 



Table go.— TTP 24-1 



43 cm. 33 cm. 23 cm. 



1938 I see I see 



1939 I msee i see i see 



1940 I msee i see i see 



I psce I dee 



I sL I sL 



I dL 



1941 I see inc ine 



The sharp lenses of 1940 at 43 and 33 cm. in TTP 24-1 (table 90) 

 are both concurrent and are interior in that they come at the start of 

 the annual increment. In contrast, the diffuse lens comes at the outer 



