THALLOPHYTA. 



685 



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

 different — in a single alliance. 



Uredinece. — 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 



^S^. 



Fig. 390.— Basidioraycetes. 



^ Clavaria aurea. ^ Dcedalia querciTia. ^ Marasmius tenerrimus. ^ Marasmius perforates. ^ Craterellus clavatus. ^Amanita 

 phalloides. 7 a portion of the basidial layer of the last-named Fungus showing the sterigmata and conidia. « Hydnum 

 imbricatuTn. ^ Polyporua p&rennis. 7x260; 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 chlamydospores, that 

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

 reproductive cells. These spores are met with in three forms in the Uredineee. The 



