284 TEXT-BOOK OF FUNGI 



family is considered by some authors as having affinity with 

 the Tuberaceae. 



Distribution cosmopolitan. 



KE Y TO SUB-FAMILIES 



Parasitic. Mycelium generally superficial, whitish, send- 

 ing haustoria into the epidermal cells of the host-plant. 

 Perithecia membranaceous, bearing various forms of highly 

 specialised hyphae or appendages. Conidia usually pro- 

 duced in chains, springing from the superficial mycelium 

 ( = Oidium ) . Erysipheae. 



Parasitic or saprophytic. Mycelium black. Perithecia 

 subglobose or depressed, sometimes bearing appendages. 

 Conidia sometimes present, but not of the Oidium type. 



Perisporieae. 



Perithecia more or less conical, simple or branched, 

 eventually becoming torn at the apex and forming an 

 opening through which the spores escape ; seated on a 

 thick, black mycelium that readily peels off the matrix. 

 Conidia are present. Capnodieae. 



Erysipheae 



All known species are obligate parasites on chlorophyl- 

 lose plants. The vegetative mycelium is superficial and 

 nourished by means of numerous haustoria which penetrate 

 the epidermal cells of the host-plant. 



Exceptions to the above general statement are met with 

 in the genera Phyllactinia and Erysiphe. In the first men- 

 tioned Palla has shown that in P. suffulta certain hyphae 

 originating from the superficial mycelium enter through 



