THALLOPHYTA. 



685 



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

 different — in a single alliance. 



JJredinece. — 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.— J3asidioraycetea. 



^ Clavaria aurea '^ DoBdaiia queicina. s Marasmius tenerrimus. ^ Marasmius per/orans. ^ Craterellus clavatus. 'i Amanita 

 phalloides. ' A portiou of tlie basidial layer of the last-named Fungus showing tlie sterigmata and conidia. « Hydnum 

 imbrieatum. ^ Polyporus perennis. ' 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 di-aws its 

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

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

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



