146 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL, I40 



been put on the alert by the two tip flushes. Two years before the 

 stained sections were analyzed under the microscope, an inspection of 

 the unstained sections under a wide-field binocular showed "probably 

 three growth layers." Should it be said that 1943 has two growth 

 layers? Two diameter flushes? Growth was quasi-cyclic in that it 

 slowed down sufficiently to leave some evidence of itself in dense- 

 wood but not enough to produce a sharply bordered growth layer — 

 it is, of course, a transitional form, a single step in a long series be- 

 ginning with a scarcely identifiable tendency to form densewood and 



Table 76.—TTP 20-27 



4.g cm. 2.7 cm. 0.8 cm. TF 



1943 I see I see 2 



I dee 



1944 I see I see i see i 



ending with a sharp, complete, entire growth layer whose intra-annual 

 nature cannot be distinguished from annual except by methods of 

 absolute dating. 



The increment for 1944 contains one diameter flush and one tip 

 flush, which is unusual for 1944 in TTP 20. Therefore, analysis gives 

 three diameter flushes for three tip flushes for two years. The years 

 are identical with previous branches, but the flushes are differently 

 located. Or, if we neglect the diffuse growth layer, there are two 

 diameter flushes for three tip flushes for two years, an analysis which, 

 in its way, testifies to multiplicity of tip flushes in a year in exactly 

 the same way that two diameter flushes to a single tip flush testify to 

 multiplicity of diameter flushes in one year. 



Table 77.— TTP 20-2S 



11.8 cm. 2.8 cm. TF 



1943 I see I 



1944 I see I see I 



I psL 



The dating of the growth layers in TTP 20-28 (table 77) is certain 

 because tip growth was measured and because the sections were cut 

 from the measured tip flushes. 



Although 1943 growth is described as sharply bordered, it is slightly 

 indefinite over a large portion of the circuit for the reason that the 

 outer four or five densewood cells are weaker and less well lignified 

 than the cells immediately to their interior. 



