DISEASES OP FOLIAGE, ETC. 35 



needles except the very youngest and weakening even 

 these. The needles are mostly short and stunted, or 

 characteristically curled. The fruiting bodies appear 

 in thin, black lines from one-eighth to one-half inch 

 in length. Sometimes the disease appears to attack 

 only certain branches; in other cases the entire tree 

 is affected. It may also enter the twigs and cripple 

 them, causing the formation of " witches' brooms." 



YELLOW WITCHES' BROOMS or WHITE AND RED FIR. 



A bright yellow witches' broom of peculiar shape ap- 

 pears on the branches of older red and white fir, due to 

 a fungus (Peridermium elatinum], which develops its 

 fruiting bodies on the deformed needles. The yellow 

 witches' brooms are very conspicuous, standing out 

 strongly against the dark green of the sound foliage. 



INCENSE CEDAR RUST. 



This disease is confined to incense cedar of all ages. 

 The same fungus (Gymnosporangium blasdaleanum) 

 causes two distinct forms of it, both of which may 

 appear, together with intermediate forms, on the same 

 tree. 



In early spring many of the small sprays of incense 

 cedar trees, from sapling to pole size, especially those 

 growing in damp gulches, appear slightly discolored. 

 On the under side, or more rarely the upper side, of the 

 green, flat, scale-like leaves a number of small, hairy, 

 brown to brick-colored tufts or cushions appear. When 

 mature, these cushions become gelatinous during the 



