AKCIDII.M-IOKM-. 



40; 



in the La'owth of tin- wood ilisturl.s tin- element.-, 80 that 

 they are irregularly developed and moiv or less twisted. 1 



A mycelium inliahits the tissues of abnormal t\vi-< and 

 cankered swelling-. It jjrows in the intercellular .-inter- ,,| 

 the rind, between the bast cells and outer part- of the wood. 

 and derives nutriment by means of haustoria : these either boiv 

 through the cell-walls, or only press closely a-ain>t them 90 

 as to cause depressions. 



Spore-formation takes place on the needle- of the witches' 

 brooms. The pycnidia ( spermo^.iuia I an- produced on tin- 

 upper side beneath the cuticle 

 and emerge through it as little 

 yellow points. The conidia (sper- 



inatia) ale tiny idoho-e colourle-s 

 1 todies. The aecidia come later 

 during June and July in irregular 

 rows on the under side of the 

 leaf. Their peridia break out as 

 low dome-like -tinctures, the 

 apici- of which rupture irregu- 

 larly to allow escape of 

 spores. In .-pite of 

 infe.-tioiis. lie I'.ary was unable 



to observe the jielietration of a 

 ^erm-tube into needles or twi^s 

 of silver lir. \\'ei-e believes that 

 infection of the lir take- place 

 on twi;_;- which ha\e jn-t emer-.-d 

 from the bud. 



A- a ].ie\entive measure, all 

 u itches 1 brooms should be cut oir 

 before .-por.-foimat ion begins, and 



stems with canker- wounds should be remo\eii during fore-t-thinnin- 

 For further detail- ilie monograph of Heck may be consulted. 



Aecidium strobilinum i.\lb. et Sch\\.r il'.riiaim. Spruce- 



'.N'nti-. |-'uitlici .li-l.iil- n|' tlir ;ui. it.iinir.il cl niluri-il in tin- I 



i|n--.i- uililii-,' IULUIII- MI. i\ l.i- i.lit.ijiii-il in (In- i;<-nn;in <-iliiii>ii ..I lln- \\nrk 

 (|.p. I'JO-J-Jli. i.i in tin i.ii_:m:i| tlii->i\l>\ ll.u l in. inn, t .1 iiHfi'iii. I / /. 



I '. i : i 



I'llln-lll |.lli.t. ) 



/ !,. i, ,/ , ii lanne. 



h rtation, 



I;. . . /,'. , -. , . d (,,(,.,,., i sii'.i. 1 1. i ' . , 1 1 . A // for i 

 /"/'/.. i MI::, i. 



