THALLOPHYTA. 



685 



is a fnrtlicr justification for the inclusion of all these families — at first sight so 

 ditibreut — in a single alliance. 



UredinecB. — These are the Rust-fungi, parasites for the most part on the foliage 

 of higher plants. They are outwardly manifest in the form of yellow or brown 



Fig. 390. — Basidiomycetes. 



i Clavaria aurea- ^ Dceäalia quercina. ^ Marasmius tenerrimus. * Murasmius per/f>raiis. ^ Craterelhts davatua. ^Ainanita 

 phalloides. ^ A portion of the basidial layer of the last-named Fungus sllowing tlie steiigniata and conidia. ^ Uydiiuui 

 imbrieatum. » Polyporua perennU. ^ x 250 ; the rest nat. size. 



spots and streaks, due to the spores, which are formed in masses on the surface. 

 The mycelium inhabits the intercellular system of the host-plant, and draws its 

 nourishment from the living cells. The spores are regarded as clilamydospores, that 

 is to say, localized, thick-walled segments of the hyphsje having the properties of 

 reproductive cells. These spores are met witli in three forms in the Uredinese. The 



