THE LICHENS 63 



Sub-class B. — Autobasidiomycetes 

 (Basidium one-celled within which either four spores or four nuclei are formed) 



Division a. — ^Hymenomycetes 



(Hymenium or spore-bearing surface exposed) 



Order i. Thelephorales, forms appearing on tree trunks as leathery 

 incrustations or as bracts on the ground, old logs, etc. 



Order 2. Clavariales, the coral fungi. Fleshy coral or club-shaped 

 forms. Ex.: Clavaria. 



Order 3. Agaricales, the mushroom or toadstool alliance. Alike 

 with the other members of the Basidiomycetes the plant body consists 

 of the mycelium, ramifying through the substratum, but the part which 

 rises above the surface (the Sporophore) is differentiated into a stalk- 

 like body called a stipe bearing upon its summit a cap or pileus, the 

 latter having special surfaces for the hymenium. 



Family I. Hydnace^ or tooth fungi. Ex.: Hydnum. 



Family 2. Pol yporace^, or pore fungi. Ex. : Polyporus. 



Family 3. Agaricace^, the gill family in which the hymenium 

 covers blade-like plates of the pileus, called gills, generally occurring 

 on the under surface of the same. Ex.: Agaricus campestris, the 

 common edible mushroom of fields; Anamita muscaria and Anamita 

 phalloides, both of which are poisonous. 



Division b. — Gasteromycetes 



(Hymenium inclosed) 



Order i. Lycoperdales, or puff balls. Ex.: Geaster, the earth 

 star and Lycoperdon. 



Order 2. Nidulariales, the nest fungi. 



SUBDIVISION v.— LICHENES, THE LICHENS 



Lichens are variously colored, usually dry and leathery plants, 

 consisting of symbioses of algae and fungi. They are found on the 

 bark of trees, on rocks, logs, old fences, etc. 



According to structure and mode of growth of the thallus, the 



