Plate 22 



Fig. I. XSC i-J-a. Brancli sectiun of Cuprcssiis ari:::<>iiica. cut May 10, 1940. 



Xylem of 1935-1940. Dated nniltiplicity ; eccentricity, with shifting long 



axis ; lensing. 



1935 : Multiple. 



1930: Natural frost effects; jL's and rhythmic d\v ; see with weak, thin dw. 



1937: Natural frost effects; see with weak thin dw ; overlapping lenses with 

 tL's and rhythmic dw ; see. 



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



1939 : see ; interior lens and frost spots connected with dw ; overlapping lens 

 with 4L's and rhythmic dw ; see. 



1940: Effects of artificial frost (of April 8, 1940); sL. 

 Fig. 2. XSC 2-i-a. Branch section of Ciiprcssus arizonica, cut May 10, 1940. 



Xylem of 1933- 1940. Dated multi])licity, 9 see for 4 years. 



1933: see. 



1934 : Circle of natural frost effects. 



1934-37 : 9 see. 



1938 : Circle of natural frost effects ; see. 



1939: see; sL. 



1940: Spots made by artificial frost of April 8. 



