Details of Plate 14. 



Figs. 



L. Larrea tridentata submerged 1906 to 1908. Only the woody cylinder was left in the specimen 

 submitted for investigation. 



M. Carboy neck showing filaments of Beggiatoa in great abundance. This culture was two weeks 

 old, having developed in the carboy shortly after specimens of fresh Larrea wood had 

 been immersed in the carboy of Salton Sea water. 



N. Larrea tridentata after two months' submergence in Lake Michigan water. Considerable 

 decortication is shown in the long sections. 



O. Culture shown in N two months later, when decortication has advanced far in the long sec- 

 tions whose ends had been twisted prior to submergence. 



P. Larrea tridentata two months after being submerged in Salton Sea water. The twisted por- 

 tions of the long specimens show great decortication, while the transverse sections are 

 entire, and there is no breaking away of the cortical zone. 



Q. Culture P two months later, when the decorticating process has advanced further. The 

 transverse section has begun to break away in the cambial region after four months of 

 Salton Sea submergence. 



R. Larrea tridentata showing cortex (c), phloem (p), and xylem (x). The unlignified zone (unlig.) 

 here is very wide, and the lignified zones are less numerous than in Prosopis glandulosa 

 or Prosopis pubescens. This is closely associated with the different types of decortica- 

 tion indicated in D, E, I, and J of plate 13, and N, P, O, and Q of plate 14. 



