Plate 14 



Fig. I. TTC 34-3-ci. Branch section of Cnprcssus arizonica, cut November 29, 



1941. Xylem of 1936-1941. Typical natural 1938 frost; sharp lenses; weak 



densewood under cambium. 



1936 : dee ; see. 



1937: Circles of parenchyma cells; injury; see. 



1938: Circle of natural frost effects; see with weak densewood. 



1939: see; sL. 



1940 : see and ddw ; sL. 



1941 : see with weakly developed dw. 

 Fig. 2. TTC 34-6-a. Branch section of Ciipressus ari::onica, cut November 29, 



1941. Xylem of 1937-1941. Gradations in marginal definition of intra-an- 



nuals, from weak and diffuse (1938) to strong and sharp (1939) ; outer thin 



growth layer. 



1937 : see. 



1938 : Circle of natural frost effects ; dee ; see. 



1939: Parenchyma circle; see (contrast with dee of 1938); see as "outer 

 thin" with weak dw and lenticular Iw. 



1940 : Natural frost effects ; bands of diffuse dw ; see ; long sL. 



1941 : see. 



Outer thin of 1939 judged to belong to 1939 because of position of frost 



effects in 1940. Figure i, plate 15, gives detail of this figure. 



