THK I'AUASITIC FUNGI. 



parasites. l The former have their vegetative mycelium spread 

 nvi-r the surface of the host-plant, the latter penetrate into the 

 plant jiinl there develop their mycelium. Both receive nourish- 

 ment fr..m the cells of the host-plants, generally by means of 

 -]M-rj;i] absorptive organs inserted into the cells of the host, the 



\V. may distinguish the following groups of parasites accord- 

 ing ID the dr-T'M- of their penetration into the organs of the 

 Im-l-plant they attack : 



1. Epiphytes: () with haustoria which only sink into the 

 miter membranes of the host; 



(//) with haustoria penetrating into the cavity of the host- 

 cells. 



2. Endophytes : (a) with a mycelium which grows in the 

 walls of the host-cell, and is generally nourished without the aid 

 of haustoria ; 



(I') with a mycelium which grows in the intercellular spaces 

 only, and is nourished with or without haustoria ; 



(c) with a mycelium which penetrates into the host-cells and 

 becomes an intracellular mycelium ; 



('/) lower fungi which live completely in a host-cell. 



1. Acquisition of nutriment by the epiphytic parasitic 

 fungi. The simplest mode of acquiring nutriment is found in 

 yeasts (Saecharomyces apiculatus, etc.) which frequent the outside 

 ut living fruits, and live on the drops of sugary solution which 

 diffuse therefrom. 2 



1 Kpiphytic parasites always produce their reproductive organs outside their 

 host-plant. In the case of endophytic parasites, the reproductive organs of 

 some are produced inside the host-tissue, e.ij. the zygospores and oospores of 

 ' 'hi/I ri'li't'-i in ami Peronosporeae, the chlamydospores of the Ustilagineae.; others 

 funii their .sporocarps wholly or partially embedded, the spores and conidia only 

 ln-iii'_' discharged externally ; while a large number form sporocarps on the surface 

 after the epidermis has been torn. Conidia are generally abjointed from the 

 free surface of the host-plant. 



The terms epiphytic and endophytic parasites have been chosen with regard to 

 the development of the parasitic food-absorbing mycelium. Some authors regard 

 epiphytism somewhat differently, and include amongst endophytes those forms 

 whieli live on the surface of the host and penetrate only by haustoria. If this be 

 > |>ted. epiphytism is very exceptional amongst parasites of the higher plants. 

 Xnpf (" Die Pilze") gives as examples of this condition only the following: the 

 /.alum/I,, in'iti-Kir inhabiting the chitinous skeleton of certain insects, and Melano- 

 ./,,,,-n j,tirn-<i/lra on filaments of species of Imria ; these have no communication 

 lietween the mycelium and their host. Species of Chaetocladium parasitic on fungi 

 :ni'l jibx.iliing the cell-wall of the host at the point of contact, could, strictly 

 -|.i-.-ikiii-_', no longer be classed as epiphytes. 



- llusgen. " Ueber einige Eigenschaften d. Keimlinge parasitischer Pilze." 

 Botan, 7-i'inii/, 1893. 



