CLASSIFICATION OF PLANTS 519 



Class III — Sac fungi. Produce spores in a sac. Examples 

 are the yeasts, powdery mildews, and many others. 



Class IV — Club fungi are so-called because their spores are 

 produced upon a club-shaped structure. Mushrooms, puffballs, 

 smuts, and 7'usts belong to this group. 



The subphylum Algae includes the chlorophyll-bearing thallo- 

 phytes. In some forms the chlorophyll is masked by some other 

 coloring matter. They range from single-celled forms to filamen- 

 tous colonies or even long ribbon or rope-like masses many feet in 

 length. They are nearly all aquatic. The subphylum Algae is 

 subdivided as follows : 



Class I — Blue-green algae contain a blue pigment in the 

 cells in addition to the green color. Examples are Nostoc prti- 

 niforme and Oscillatori violacea. 



Class II — Green algae are of countless forms, unicellular, 

 filamentous, platelike, and in irregular masses of cells. There 

 are both fresh-water and salt-water forms, and others live on 

 land. One form will grow on snow patches. Pleurococcus vul- 

 garis and Vaucheria terrestris are examples. 



Class III — Brown algae are nearly all marine plants. 

 Thev are the commonlv known seaweeds. 



Class IV — Red algae are mostly marine. Our most deli- 

 cate and beautiful seaweeds belong to this main class. 



II. Phylum — BRYOPHYTA (Gr., hryon — moss; phyton — 

 plant). Contains only two classes, the liverworts and the mosses. 

 These plants are small and live mostly on land. They show a 

 greater development of tissues ^ than the algae and may be 

 either thallus-like (liverworts) or have stems with rootlike pro- 

 jections and very simple leaves. They reproduce by forming 

 spores. 



III. Phylum — PTERIDOPHYTA (Gr., ^p^m^ — fern). This 

 includes a group which, when the world was younger, played a 

 very important part in the vegetation on the earth. Most coal is 



