438 Notes on Parasitic Ascomycetes. — //. [Sess. 



V. Kunzei Sacc, on wild rasp and bramble ; F. Dickiei 

 B. & Br., on Linncea horealis ; and V. potentillce (Fr.) Cke., 

 on silverweed. 



Stigmatea Rdbertiani Fr., parasitic on leaves of Herb-Eobert, 

 is abundant almost everywhere. The perithecia appear as 

 shining black dots, generally congregated in groups, and often 

 very numerous on a single leaf. Among less common repre- 

 sentatives of the genus are >S^. geranii (Grev.) Fr., on various 

 species of cranesbill, and *S^. ranunculi Fr., on leaves of 

 buttercup. 



The genus Sphcerella includes a considerable number of 

 species, most of which must be reckoned as saprophytes. 

 Among the parasitic forms may be noted S. rumicis (Desm.) 

 Cke., which produces little circular clusters of perithecia on 

 foliage of blunt-leaved dock ; S. microspila (B. & Br.) Cke., on 

 willow-herb; S. innumerella Karst., on marsh cinquefoil; and 

 S. iridis Awd., on yellow flag. 



As the result of recent investigations and experiments 

 conducted by mycologists on the Continent, the number of 

 Pyrenomycetes alleged to be parasitic in their early stages 

 has been considerably increased. In particular, it is stated 

 that certain Sphseropsidese, Hyphomycetes, and other fungi of 

 a low type, which occur as parasites on living trees and 

 shrubs, and were formerly described as independent " species," 

 have now been determined to be merely stages in the life- 

 history of species of Gnomonia, Venturia, Sphcerella, or other 

 genera of Pyrenomycetes. In the meantime, however, it is 

 desirable that before the conclusions arrived at on the 

 Continent are accepted as equally applicable to species found 

 in Britain, they should be confirmed by similar experiments 

 conducted in this country. This is the more necessary in 

 cases where the alleged ascigerous forms of well - known 

 parasites have not as yet been reported as occurring in 

 Britain. 



