354 DISEASES OF CULTIVATED PLANTS 



characterised by having the spores borne on gills or lamellae, 

 usually placed below the cap or pileus. 



ARMILLARIA 



Pileus symmetrical, more or less fleshy; gills adnate or 

 slightly decurrent ; stem central, furnished with a ring ; 

 spores white, elliptical. 



Beech agaric (Armillaria mucida, Schrad.) is a wound- 

 parasite on the beech. At High Beech, Epping Forest, 

 where this fungus is abundant on the beeches, its ravages are 

 very evident in the way of wounds of a canker type, which 

 eat deeply into the wood and may in course of time cause 

 branches to be broken off by wind ; beyond this it cannot 

 be considered as a really destructive parasite. Its attacks 

 are mainly confined to old trees, where it gains an entrance 

 through broken branches, holes made by woodpeckers, etc. 

 I broke off a healthy, fairly thick branch of a beech and 

 placed spores of the fungus on the wounded part. At the 

 end of the second season, after inoculation, the branch was 

 killed for a considerable distance back, and the sporophores 

 of the fungus were developed in abundance at the wounded 

 portion of the branch. 



. Usually growing in clusters ; pileus 1-4 in. across, sub- 

 globose, becoming almost plane, mucilaginous, whitish or 

 grey ; gills broad, white ; stem 2-5 in. long, thickest at the 

 base, white, often with dark squamules, ring thick, spores 

 elliptical, 14-16x8-9^. 



Tree root rot (Armillaria mellea, Vahl.) is undoubtedly 

 the commonest and most generally distributed of any British 

 fungus ; it is also far from uncommon in many other 

 countries. It is generally considered as a saprophyte, as it 

 occurs in abundance around dead stumps, on logs, etc., and 

 probably it may at times begin and pass through life as a 

 pure saprophyte. It is highly probable that in most instances 

 it has been more or less responsible for the death of the 

 stump or log on which it is growing. In some instances the 

 fungus appears to be growing directly out of the ground, but 

 in such instances careful examination will show that it is 

 attached to buried wood, roots, etc. Practically all kinds 

 of trees, both broad-leaved and conifers, are attacked. The 



