10 



THE PARASITIC FUNGI. 



Others, like Fodosphacra castagnci, they take the form of broadened 

 closely-clinging hyphae with haustoria. Frank describes a swell- 

 ing of the germ-tube of Fusidadium trcviulae just before the 

 infecting hypha pierces the cell- walls of its host. A similar 

 phenomenon can be observed in Folystigma rubrum, in G-nomonia 

 crythrostoma, and in the germinating aecidiospores of Mclampsora 

 Gocppcrtiana. Some other examples will be mentioned in our 

 next section. 



Haustoria of the epiphytic Parasites. 



The most inconspicuous haustoria are those of Hcrpotricliirr 

 nigra and Trichoqdwcria ri«-'i'ttsitica, described liy l\. Hartig.^ 



Fkj. 2. — Haustoria of Tnchosphaeria parasitica. (Details on Fig. S8.) 

 (After R. Hartig.) 



They are tiny hyphal processes resting on the host-epidermis, 

 and sunk into the outer walls of the epidermal cells, so as to 

 pierce the cuticle but not the whole wall (Fig. 2, d, e; also 

 Fig. 90). The Erysipheae are typical epiphytes, which weave 

 a mycelium over the surface of plants they attack ; the 

 mycelium retains its hold by adhesion-discs or appressoria, and 

 from certain parts of these a fine thread-like process is given 

 off, which, after piercing the epidermal wall of the host, swells 

 inside to a simple or branched sac, the haustorium. The 



^ Lehrhuch d. Baiimkrankheiten, II. X\ 

 Somerville. Macmillan & Co., 1894. 



English translation by Professor 



