206 SALMON : SUPPLEMENTARY 
adheres to the substratum, and hardens, so that a reattachment of 
the perithecium, in a reversed position, takes place, and so firm is 
this attachment that some force is necessary to remove the peri- 
thecium with a needle. This curious phenomenon can easily be 
observed in nature, since on most host-plants perithecia are to be 
found late in the season attached to the upper surface of the 
leaves—a position in which they could not, in most cases, have 
originated, but which is to be explained by their having dropped 
off from the under surface of higher borne leaves, and become re- 
attached by the mucilaginous cells. , This reattachment has been 
the cause of leading systematists into several curious errors. In 
the first place there is no doubt that the numerous herbs given as 
hosts for P. corylea are not hosts in the true sense of the word at 
all, but are merely the plants to which perithecia, blown by the 
wind or fallen from the leaves of trees above, have become attached 
in the manner just described. Neger (53) records the occurrence 
of perithecia transferred in this way to plants of Vola, Urtica, 
Onobrychis, Lamium, etc., which were growing under a tree of 
Corylus attacked by P. corylea. Saccardo (66) records on Plantago 
lanceolata perithecia of P. corylea “evidently proceeding from 
leaves of trees.’’ I have seen perithecia firmly attached to the 
wood of -raxinus (see monograph, p. 234), and they have been 
recorded also on grasses and on Pertusaria by Bagge (see Fuckel, 
Symb. Myc. 80). The fungus recorded as “ Erysiphe graminis 
DC.?” on the leaves and stems of Poa nemoralis and Festuca syl- 
vatica by Richon (Cat. Champignons de la Marne, 232, 1889) with 
the description “ Les périthéces sont ornés de 6 ou 8 appendices 
simples et renflés 4 la base. II constitue probablement une variéte 
de Phyllactinia suffulta non signalée par les anteurs et différente de 
| Evysiphe graminis de Saccardo,” may now safely be identified as 
P. corylea. ‘ Erysiphella Carestiana Sacc.”” was founded on peti- 
thecia attached by means of their penicillate cells to the pileus of 
Fomes fomentarius. There seems also every reason to believe that 
the “ Exysiphe fungicola” of Schulzer on Boletus duriuculus is 
nothing more than P. corylea. Hazslinszky (27, p. 181) gives the 
following description of the fungus: (I am indebted to Professor 
A. Magocsy-Dietz for the translation from the Hungarian ) = 
‘ Perithecien zerstreut und nicht zahlreich, winzig ; auf einem aus 
