1 86 transactions of royal scottish arboricultural society. 



Tree-Growth in 192 i. 



Tree-growth during the past growing season has been 

 generally satisfactory. The long continued spell of dry weather 

 which was experienced has not had the same effect on 

 established plantations as it had upon field crops, and especially 

 in Scotland, even nursery stocks suffered much less injury than 

 might have been expected. Early frosts were not unduly 

 severe, and buds and shoots have ripened in a normal manner. 

 The check to growth in its earlier seasonal activity might 

 have been expected to result in secondary or prolonged growth 

 in autumn, but such was not the case. The absence of 

 Lammas shoots in autumn was remarkable in many places. 

 This was no doubt due to the continued relatively dry conditions 

 during the later stages of vegetative activity. 



Autumn foliage in its various tones and tints usually appears 

 at its best when mild moist conditions during the earlier stages 

 of vegetation in spring are followed by dry sunny weather in 

 autumn. In the past autumn the intensity and variation in 

 colour was late in appearing and of short duration, and the 

 leaf fall was considerably later than usual. 



ARMILLARIA MELLEA as a Potato Disease. 



Armillaria melka, the Honey Agaric, is well known as a 

 disease of both coniferous and broad-leaved trees, and is 

 remarkable for the number and variety of species which it may 

 attack. Its occurrence on the potato is, however, very unusual, 

 and it has not been recorded on this host, up to the present, in 

 this country. It has, however, been recorded as a potato disease 

 from Japan and also from Australia, where it was described in 

 New South Wales, in 1910, by H. T. Johnson. This investigator 

 states that the rhizomorphs of the fungus grow over the tubers, 

 penetrate them at certain spots, and bring about the destruction 

 of the tissues, so that ultimately the whole tuber becomes rotten. 

 He adds that the disease has been spreading for several years 

 in the affected district. 



The specimens which are the subject of the present note were 

 collected by Mr Mitchell, forester at Rosebery, Midlothian, 

 and were forwarded through the headquarters of the Forestry 

 Commission in Scotland. The dark brown rhizomorphs of the 



