THE BLUEING OF CONIFEROUS TIMBER. 85 



2. The Pilifera group with long-necked perithecia which 



includes : — C. piceae, found commonly in the sapwood of 

 spruce and fir ; in this, in addition to perithecia, conidial 

 forms of the Graphium and Cladosporium types are also 

 present. C. cana and C. coeridea on pine wood closely 

 resemble C. piceae, but there is no Graphiu?7i form in the 

 life-history of C. coerulea. 



3. Endoconidiophora coerulescens resembles the three previous 



species but possesses hairy perithecia, and is characterised 

 by its conidia which are produced in a short row at the 

 ends of upright conidiophores ; the stage was previously 

 known as Chalera Ungeri. 



Of the above species two, Ceratostomella piceae and C. pint, 

 have been found in this country by Dr Macallum in " blued " 

 timber of the Scots pine. The development of C. piceae has 

 been worked out in detail by this investigator, and her results 

 with regard to the conidial stages present confirm those of 

 Miinch, both Graphium and Cladosporium types being definitely 

 part of the life-history. C. piceae does not appear always to 

 produce the blue staining characteristic of the other species, 

 and in Scotland spruce timber may be quite unstained even 

 when perithecia occur thickly all over the surface. 



Little information is available as to spore distribution. The 

 ascospores in C. piceae, after discharge, are found at the end of 

 the perithecial neck in a mass of shiny yellowish slime which is 

 insoluble in water. Conidia of the Graphiu^n type are found 

 in the drop of liquid borne on the head of the fructification, 

 while those of the Cladosporium type develop freely both on 

 special conidiophores and on the ordinary mycelium. It is 

 improbable that the ascospores are distributed by wind, but the 

 conidia, after drying, may be spread by this method. The 

 conidia of Endoconidiophora coerulescens are sticky, and Miinch sug- 

 gests that they may be carried by insects. Von Schrenk, however, 

 failed to demonstrate the presence of spores of Ceratostomella 

 on bark-boring beetles. Judging from the rapid infection of 

 timber stacked in the forest, it appears probable that some 

 distribution by wind takes place. 



The effect of species of Ceratostomella upon the tissues has 

 been described by several investigators. The hyphae, which 

 are at first colourless, are found principally in the medullary 



