341 . 



THE PYRENOMYCETES 

 AND SOME PROBLEMS THEY SUGGEST.* 



Sir H. C. HAWLEY, Bart. 



' What are we to understand by the term Pyrenomycetes ' ? 

 Fries regarded as genuine Pyrenomycetes all fungi with asci 

 developed in closed and ostiolate perithecia, but grouped with 

 them all whose fruit was produced in closed bodies of any 

 description and whether in asci or not. Many of the latter 

 would now be classed as ' Fungi Imperfecti/ as probable stages 

 in the life-history of true Pyrenomycetes. 



Most mycologists of the present day are inclined to confine 

 the Pyrenomycetes to the Sphaeriacci in the sense of Berkeley 

 and Cooke, and even thus restricted they form a group as ex- 

 tensive as they are interesting. They have been somewhat 

 neglected in this country. The principal reason for this in- 

 attention is the want of an up-to-date English Systematic Text 

 Book. But they offer great attractions to the mycological 

 student. The specimens are at their best in Winter and early 

 Spring when there is a little else to be met with, and, unlike 

 most other fungi, may be put aside and preserved for an in- 

 definite length of time ; their fruiting characters affording 

 very diversified and beautiful objects for study they certainly 

 deserve more attention than they get. 



The value, or otherwise, of a stroma (a fungoid growth in 

 which the perithecia in some species are imbedded) as one of 

 the characters used in classification is worthy of discussion ; 

 also, the immersion of the perithecia in the matrix of the plant 

 substance in which it is growing, contrasted with their super- 

 ficiality. 



Spore characters in relation to colour and septation in 

 many species are of importance. In some cases, however, it 

 is necessary to be certain the perithecia under examination are 

 mature ; if not, the results of the examination are misleading. 

 The spores of some species only acquire colour, or become 

 septate late in life. If their position therefore depends on one 

 of these characters, we must be sure that we are dealing with 

 mature specimens. In one specially difficult family, Lophi- 

 diiim compressum is an example of a troublesome species whose 

 spores pass gradually through every stage from hyaline and 

 continuous, to coloured and muriform ; and probably at some 

 time or other it has been mistaken for most of the species in 

 the Lophiostomaceae ; indeed in this family, the slow develop- 

 ment of the spores, together with the presence in certain 



*Abstract of Paper read at the Yorkshire Naturalists' Union Fungus Foray 

 at Sandsend. 



1912 Nov. I. Z 



