FUNGI ATTACKING CONES. 



473 



there being at least two aecidia on each scale of the affected 

 cones. After the aecidia burst and disperse their spores, pale 

 spots are left on the scales. 



Fig. 230. Spruce cone attacked 

 by Aeeidium strobilinwn, Ess. 



Fig. 231. Sporophores of A. 

 strobilinum, Alb. et Schw., on 

 the under surface of a scale of 

 a spruce cone. 



SECTION III. FUNGI ATTACKING BROADLEAVED TREES. 



The numbers of dangerous fungi attacking broadleaved 

 trees may be limited for description here, to eight, besides 

 some wound-parasites. The most destructive are marked 

 with an asterisk, as in the list given on the next page. 



A. Boot-fungi. 

 *1. Rosellinia quercina, E. Hrtg. 



a. Description and Life-history. 



The leaves of infected 1 to 3 years old oak seedlings become 

 gradually pale and at length dry up. This commences with 

 the topmost leaves and proceeds downwards. At the top of 

 the taproot just below the surface of the ground, the bark 

 and wood turn brown and shrivel up, and this at length 

 spreads to the whole taproot and the plant dies. On pulling 

 up the plant and examining its tap-root, black spheroidal 

 sclerotia of the size of a pin's head are seen, which spring 

 from numerous brown rhizornorphs, which have branched 

 freely and surround the plant's roots, and are prolonged into 



