THE ALG^E-FUNGI (PHYCOMYCETES) 225 



characteristic of the class. Thus phycomycetes literally means 

 " seaweed fungi," and we call them algse-fungi ; ascomycetes 

 means "sac fungi," since some of the spores are formed in a 

 peculiar sac ; and the basidiomycetes are the " stalk fungi," or 

 " club fungi," since some of the spores are borne upon a stalk 

 or club-like base. In each of these classes many kinds of fungi 

 are found, but only a few kinds in each class can be consid- 

 ered in an elementary treatment. 1 The lichens are peculiar 

 plants, which are treated in this connection merely for lack of 

 better classification for them, as will appear later. 



218. Classification: 



Thallophytes 

 Algae 

 Fungi 



Class I. Phycomycetes. Leading genera used as illustrations, 

 Rhizopus (bread mold), Saprolegnia (water mold), Plasmopara 

 (grape downy mildew), Phytophthora (potato blight), Cystopus, 

 and others 



Class II. Ascomycetes 

 Class III. Lichens 

 Class IV. Basidiomycetes 



1 The " slime molds," or myxomycetes, are usually classed with the fungi, 

 though some students regard them as animals. They often appear as ge- 

 latinous, sticky, yellow, brown, or brightly colored masses exuding from 

 crevices in old stumps, logs, old board walks, upon decaying leaves, and 

 sometimes upon very rich soil (Fig. 182). At other times these masses pro- 

 duce stalks, globules, or one or a few rounded masses. These are the spore- 

 producing structures. So different are these two stages one motile like 

 some of the lower animals, the other forming spores like some plants that 

 students formerly thought the two stages were different organisms, of which 

 one was animal, the other plant. 



