Plate 15 



Fig. I. TTC 34-6-a. Enlarged detail of figure 2, plate 14. Xylem of 1939-1941. 

 Multiplicity of gls in annual increments ; variation of dw development; "outer 

 thin" gls; intra-annuals indistinguishable from annuals. 

 1939: 2 see, dw band of inner gl stronger than dw of annual. 

 1940: Effects of natural frost; 2 see, dw band of inner gl nearly the same 



strength as dw of annual. 

 1941 : see. 

 Fig. 2. TTC 36-3-b. Branch section of Ciiprcssiis ari::oiiica, cut January i, 1943. 

 Xylem of 1940-1942. Dated multiplicity ; heavy dw of intra-annual. 

 1940: Rhythmic dw ; 2 see, inner dw heavy. 

 1941 : Parenchyma circle ; faint dee ; see. 

 1942: 2 see, dw of inner gl heavier than dw of outer gl, outer contacts of 



both gls slightly irregular. Elsewhere on section, dw of inner gl 



splits apart with insertion of Iw cells. 



