i66 DISEASES OF CULTIVATED PLANTS 



Many other equally ill-defined species form black films on 

 various trees, shrubs, and herbs, as oak, olive, lime, hazel, 

 speedwell, various grasses, etc. 



Prillieux, Malad. des Plantes Agric., 2, p. 44 (1879). 



Capnodium dtricolum (M' Alpine), known as 'black blight' 

 in Australia, where it is widely distributed on the leaves and 

 fruit of oranges and lemons. Like allied forms it is not a 

 parasite, but follows in the wake of honey-dew deposited by 

 insects, hence the remedy consists in preventing the deposition 

 of the honey-dew by using an insecticide. 



M'Alpine, Proc. Linn. Soc. N. S. Wales, p. 469 (1896). 



ASTERULA (SACC.) 



Perithecia seated on black, radiating, subsuperficial 

 mycelium, depressed, almost mouthless ; asci generally 

 8-spored ; spores continuous, hyaline. 



Asterula beyerinckii, Sacc. ( = Ascospora beyerinckii, Vuill.), 

 is considered by Vuillemin as the ascigerous condition of 

 Coryneum beyernickii (Oud.), but the point has not been 

 definitely determined. 



Ascigerous condition. Mycelium plentiful, crustaceous ; 

 perithecia globoso-depressed, mouth very minute or absent, 

 100-130 /A diam., black, carbonaceous, erumpent, asci 

 numerous, up to 40, obovate then cylindrical, 110X20 /* ; 

 spores elliptical, continuous, hyaline, 17x57 /x. 



Conidial form = Phyllosticta beyerinckii (Vuill.). Perithecia 

 globose, surrounded by septate hyphae, 150/4 diam., conidia 

 elliptical, hyaline, 6 X 5 /*, extruded as a viscid tendril. 



Vuillemin, Journ. de Bot., 2, p. 255 (i 



PYRENOMYCETES 



The members of the present group are comparatively 

 legion, and occur in every part of the world where higher 

 forms of plant life exist to serve as hosts. The structural 

 characteristic of the family is the perithecium or fruit-case, in 

 which the asci containing the spores are produced. The 

 perithecium varies in form from globose to flask-shaped, and 



