462 



BASIDIOMYCETES. 



scales arranged regularly in concentric lines. The stools break 

 out from living stems through cracks in the bark or from wounds, 



e.g. those made by wood-peckers. 



The fir-wood, normally white, assumes, 

 when diseased, a yellow or honey-colour, 

 more or less like the sporophore, while 

 here and there, parts may become light 

 brown. The hyphae grow in all direc- 

 tions, but especially as white strands up 

 and down the year-rings, while others 

 in horizontal and vertical direction break 

 up the wood into irregular patches 

 (Fig. 290). In the final stages of 

 destruction the wood will be found 

 laminated into its separate year-rings 

 and very much broken up into irregular 

 pieces (Fig. 291). 



The sporophores of this Agaricus are 

 not uncommon protruding from bark- 

 cankers caused by Accidium clatinum, 

 and its mycelium assists in the destruc- 

 tion of the stem. 



Agaricus (Pholiota) squarrosus (Mill!.). On 

 living and dead stems of broad-leaved trees. 

 (Britain.) 



Ag. (Ph.) destruens (Brond.). On living 

 and dead stems of poplar. (Britain.) 

 Ag. (Ph.) aurivellus (Batsch.). On living and dead stems of broad-leaved 

 trees. (Britain.) 



FIG. 292. Agaricus adiposus 

 and Polypon'x Hm'litiii. Destruc- 

 tion of Fir- wood, the boundary 

 of the regions affected by the 

 two fungi is formed by a very 

 dark line of demarkation. To 

 the right the destruction is that 

 produced by Poti/poroi'.x Hartigii, 

 to the left by Agaricus ndiposux. 

 (v. Tubeuf phot.) 



" FUNGI IMPERFECTI." 



The fungi placed here have life-histories which as yet have 

 not been completely investigated, most of them being known 

 only in the form of pycnidia or conidia. The number of species 

 was at one time much larger, but it is gradually being re- 

 duced as the forms are proved to be stages in the life 

 of some species of definite systematic position in the other 

 groups already considered. 



The group may be divided into the provisional sub-groups, 

 the Sphaeropsideae, Mdanconieae, and Hyphomycetes. 



