Plate I. 



;?. Mfliitosli on its own roots. 



Fig. k McInto.sh on 01denl)urg roots. 



(Figures 3 and t are on approximately the same scale. Tlie api)arent ditterence 

 in the size of the screen is dne to the fact that in Fienre \ tlie screen was Iield 

 considerahlv fartlier from the tree than in Fiaiirc :i.) 



