240 ANNALS OF SCOTTISH NATURAL HISTORY 



troublesome weeds of both arable land and pasture or hayfields, 

 e.g. thistles, dandelion, and their allies, ribwort and broad -leaved 

 plantains, docks and sorrels, tall oat-grass, couch-grasses, etc. 



But consideration of these results of man's actions and of the 

 flora which he has been the means, often unintentionally, of intro- 

 ducing, and in part of establishing, around Aberdeen, must be 

 deferred. 



TREE-DISEASES DUE TO FUNGI. ADDITIONAL 

 SCOTTISH RECORDS IN 1910-11. 



By CHARLES O. FARQUHARSON, M.A., B.Sc. 



IN making a collection of tree-diseases due to cryptogamic 

 parasites the following new occurrences were noted. They 

 are mainly from the district round Aberdeen. 



i. Yew Leaf Scorch. This disease occurs at Durris on 

 several old park trees in the grounds of Durris House, 

 where it seems to be working a considerable amount of 

 damage. The parasite is SpJuzrulina Taxi (Massee). The 

 dead leaves showed an abundance of sunken perithecia, 

 which proved to belong to two fungi. One of these was 

 Anthostomella Rehmii (Thiim.), a saprophyte. A specimen 

 of this was sent to Kew for confirmation, and on this the 

 conidial stage of the Sphaerulina was detected. Mr. Massee, 

 regarding this disease, makes the following note (" Diseases 

 of Cultivated Plants and Trees," 1910): "As a rule when 

 this parasite once attacks a tree it spreads very rapidly, so 

 that within a short period all the leaves have fallen ; many 

 of the younger shoots are also killed and fall to the ground. 

 If the disease attacks a tree for two or three years in 

 succession, it is usually killed outright." As yet it has not 

 been recorded from many localities, and none of these are in 

 Scotland. 



ii. Douglas-Fir Disease. Several diseases of Douglas 

 Fir are found commonly in Aberdeenshire, viz. Sderotinia 

 Fuckeliana (De Bary), ( = Botrytis Douglasii, Tubeuf.), and 

 Plioma pitliya, Sacc. ; but neither of these can as yet be said 

 to be a serious pest. The Phoma is generally on the leader 

 shoot of young plants, and it is difficult to say whether frost 



