Mil lAl.ls.M. 





the ease of the so-called " storm-tirs ' of the mountains, mi 

 which are developed not a single apex, as in the normal h'r, 

 luc many, each of which grows up like a little indri.nid.MH 

 bree on the branches of the old stem. A similar iv-nlt follows 

 where a portion of a lateral branch is planted as a "cutting," 

 oiir bud grows directly upwards, the others form lateral branches. 

 The stimulating e fleet which the removal of the terminal shoot 

 produces on lateral branches is thus one which extends to a 

 considerable distance. A stimulus of a somewhat similar nature 

 appears to be exerted on buds attacked by certain t'uimi, so 



I''.. Witch..--' liru.ini "f Sihvr l-'ir, 



I ulic'if ).lx.t.) 



liy .-/,.-../ 



that the shoot produced from such a bud no longer retains its 

 normal direction of -rowth, but becomes negatively -cotiopjc. 

 like an independent plant. This marked negative -eotropism 



i- characteristic of all witches' brooms (Fig. l ( >>, and show- 



cl.-arly that tln-y are no longer coin mllod by the same laws of 

 A'th as the normal lateral branches. Th.-y ha\e in addition 

 other pi-'idiarities not exhibited by normal plants. Thus the 

 witches' brooMi of the silver tir caused by mycelium o| 

 .I.--///////// iluli n ii Hi is not evergreen, but be-u- nerillrs which 

 fall e;irh autumn. Moreover, no uitclie-' broom l.rar> ll"\. 

 or fruit; for r\amplr that on tin- ch.Mi-\ < |-'j-. 5) produces 



e\clll>i\el\- lr:i!'-lillds which Ullfold s, | ,, i| ) ( ;, | ,eol | sly \\jlll tile 



