CHAPTER VII 



THE LOWER BASIDIOMYCETES 



(Rusts and Smuts} 



The third class of fungi known as the Basidiomycetes contains 

 two series of organisms very dissimilar in habit, the first series para- 

 sitic on plants, and the second series forming the saprophytic forms 

 of mushrooms and puff balls that constitute not only the highest 

 types of fungi but at the same time those that are popularly most 

 widely known. The class Basidiomycetes is composed of twelve 

 orders which may be separated as follows : 



1. Parasitic on spermaphytes, often deforming the host ; mostly inconspicu- 



ous ; (rusts and smuts). 2. 



Saprophytic, mostly gelatinous, fleshy or woody fungi, usually conspicu- 

 ous ; terrestrial or epixylous, rarely parasitic on other fungi of their 

 own class. 3. 



2. Producing in ovaries or leaves, smut-like chlamydospores from which the 



basidia-like conidiophores arise in germination. I. Ustilaginales. 

 Producing black, brown or yellow rust-like pustules under the epidermis 



of leaves or stems, or developing clusters of crater-like openings with 



spores formed in chains inside a membranous pseudoperidium. 



2. Uredinales. 

 Producing whitish spots, pustules or inflated galls mostly on Ericaceae ; 



basidia clavate with small sterigmata. 6. Exobasidiales. 



3. Gelatinous fungi with divided basidia. 4. 

 Gelatinous fungi with long clavate two-forked basidia ; spores dividing 



before germination. 5. Dacryomycetales. 



Fleshy, coriaceous or woody fungi with undivided basidia. 5. 







4. Basidia divided crosswise (septate). 3. Auriculariales. 

 Basidia divided obliquely or lengthwise, commonly into four parts. 



4. Tremellales. 



5 Spores arising from basidia which form a distinct membranous hymenium* 



naked at maturity, and covering the surface of gills, pores, or spines. 



( Hymenomycetes ; mushrooms, bracket fungi. ) 7. Agaricales. 



Spores arising from basidia enclosed within a definite peridium. ( Gas- 



teromycetes. ) 6. 



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