236 CLASSIFICATION OF PLANTS AND ANIMALS 



Class I. The tube fungi (Phycomycetes) , so called because of tbeir tubular bodies. An example 



is bread mold. 

 Class II. The sac fungi (Ascomycetes) , which produce spores in an ascus or sac. Examples 



are the yeasts, powdery mildews, and many others. 

 Class III. The basid'ium fungi (Basidiomycetes) , so called because their spores are produced 



in a club-shaped structure called a basidium. Mushrooms, puffballs, smuts, and rusts 



belong to this group. 



The Algoe are a very large group of chlorophyll-bearing plants, although 

 in some forms the chlorophyll is masked by some other coloring matter. They 

 have many forms, ranging from single cells to filamentous colonies or even long 

 ribbon or rope-like masses many feet in length as in some seaweeds. They are 

 nearly all aquatic. The algae are subdivided as follows : 



Diatoms 

 (highly magnified) 



Blue green Green 



(highly magnified) 



Algae. 



Brown 

 (ro natural size) 



Red 

 (235 natural size) 



I. The Di'atoms, one-celled algae having beautifully sculptured cell walls. Many are motile 

 and are important sources of food for small fish and other water-living forms. About 12,000 

 species are known. 



II. The Blue-green algce contain a blue pigment in the cells in addition to the green color. 

 Some common forms are Nostoc and Oscillatoria. About 1200 species have been named. 



III. The Green algce are of countless forms, unicellular, filamentous, plate-like, and in 

 irregular masses of cells. There are both fresh -water and salt-water forms, and others live on 

 land. The so-called "Red snow" is a form living in snow patches. Pleurococcus and vau- 

 cheria are also examples. Some 5000 species have been described. 



IV. The Brown algce are nearly all marine plants. We know them as seaweeds. About 

 1000 species are known. 



V. The Red algce, mostly marine, are our most delicate and beautiful seaweeds. There 

 are about 3000 named species. 



II. The Bryophytes (Gr. bryon, moss; phyton, plant), consist of two groups 

 of plants, the liverworts and the mosses. Both are small plants and nearly all 

 live on land. They show a much greater development of tissues than the algae^ 

 and may be either thallus-like (liverworts) or have stems with rootlike projec- 

 tions and very simple leaves. There are about 16,000 known species. 



in. The Pteridophytes (Gr. pteris, fern), are a group which, when the world 

 was younger, played a very important part in the vegetation on the earth. 

 Some coal is made very largely from their bodies. They have true roots, 

 stems, and leaves, but reproduce like the mosses, by forming spores. . The 

 Pteridophytes include three classes, the true ferns, the horsetails (Equisetum), 

 and the ly'copods or club mosses. There are about 8000 known species. 



