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 



Fig 390 — Basuhomycetes. 

 ^ Clavaria aurea ^ Dcedalia quernna. ^ Marasmius tenerrimus. * Marasmius perforam. ^ Craterellus davatus. ^Amanita 

 phalloides. ? A poitiou of the basidial layer of the last-named Fungus showing the steiigniata and conidia. » Uydnwn 

 imbricatum. » Polyporus perennis. 7x250; 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 

 j 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 Urediueae. The 



