HYPHOMYCETES. 497 



The group is subdivided into the families of the Mucedineae, 

 Dematieae, Stilbeae, and Tubercularieae} 



I. FAM. MUCEDINEAE. 



1. Sect. Amerosporae. 

 1. Subseci. Micronemeae. 



Oospora. 



Conidia, transparent or only slightly coloured, globose or 

 ovoid, non-septate, and produced in regular chains from simple 

 short conidiophores ; they thus resemble the genus Torula in the 

 Dematieae. 



Oospora scabies Thaxt.^ is said to cause the well-known 

 scab or scurf on beet and potato. This consists in portions of 

 the surface of the subterranean tubers swelling out as rough 

 brown excrescences. Other authors ascribe this disease to 

 bacteria. 



Microstroma. 



Conidia unicellular, transparent, oval, and shortly stalked. 



Microstroma album (Desm.). This, although common on 

 living leaves of several species of Quercus, is not a serious 

 disease. The conidial patches on the under side of the leaves 

 are white and very thin. (Britain.) 



M. juglandis (B^reng.) frequents the leaves of Juglans regia 

 and J. cinerea in Europe and North America. 



Monilia. 



Conidia oval or spindle-shaped, and produced in chains from 

 branched conidiophores. 



Monilia fructigena Pers. (Britain and U.S. America.) This 

 is the cause of certain widespread diseases — the brown-rot of 

 cherry and plum, the peach-rot, and a rot on apples and pears. 

 It has been the subject of many papers since Thlimen first 

 described it in 1879.^ All parts of the host are attacked, and 



^This is the arrangement followed by Massee, "British Fungus Flora," Vol. 

 III.; there the characters of the various sub-divisions may be obtained. (Edit.) 



''Thaxter, Connecticut Agric. Exper. Station, Report, 1890. 



^ Amongst the more important descriptions are : Thumen, Fungi Pomicola, 

 1879 ; Smith (Worth. G.), Gardener's Chronicle, 1885, p. 52 ; Arthur, New York 

 Agric. Exper. Station, iv., 1885. 



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