84 TRANSACTIONS OF ROYAL SCOTTISH ARBORICULTURAL SOCIETY. 



are barely visible to the naked eye and are provided with long 

 thread-like necks. Timber cut and stacked in the open in the 

 forest is particularly liable to be attacked, and up to the present 

 the disease has been observed in Scotland in the timber of 

 Scots fir, spruce, and silver fir, although that of other species 

 of conifers is also likely to become infected. It may be pointed 

 out that the species of Ceratostomella usually only attack 

 coniferous timber, and that the bluish-green rot of timber of 

 hardwoods is due to an entirely different fungus, Chlorosplenium 

 aeruginosiem. 



Von Schrenk^ and Hedgecock - have investigated "blueing" 

 in the United States, especially in the case of the timber of the 

 western yellow pine {Pinus ponderosd). The latter investigator 

 has described a considerable number of species of Ceratostomella 

 which cause "blueing" in the timber of various conifers and 

 also a number of hardwoods. These are distinguished partly 

 by differences in the shape and size of the perithecia, but 

 chiefly by variations in the form of the conidial fructifications 

 which are produced by them in great abundance. He also 

 describes the blackening of timber by species of Graphiufn, 

 a genus producing only conidial fructifications consisting of 

 a stalk made up of a number of parallel hyphae and a swollen 

 head which bears the conidia. Munch,^ in Germany, has given 

 a very complete account of the fungi producing "blueing" 

 in coniferous timber. He finds that Ceratostomella pilifera 

 is made up of a number of species, and distinguishes the 

 following : — 



I. C. Fini, the commonest species, which only attacks timber 

 of Finns sylvestris and quickly produces a decided blue 

 coloration. The bark of trees infected by this species 

 separates from the wood, and the latter becomes covered 

 by a black mass of mycelium, embedded in which are 

 the rather short-necked perithecia, and also elongated 

 sclerotium-like bodies consisting of brown cells; a second 

 type of conidium resembling that of Cladosporium is 

 also present. 



^ Bureau of Plant Industry, U.S. Dept. Agriculture Bull. 36, 1903. 



""Studies upon some Chromogenic Fungi which discolour Wood," 

 Missouri Botanical Garden, 17th Annual Report, 1906, p. 59. 



^ " Die Blaufaule des Nadelholzes," Naturwiss. Zeitschrift Forst-und 

 Landwirtschafl, 1907-S. 



