260 INTRODUCTION TO BOTANY 



that a single plant {Polyporus squamosus) may produce as 

 many as 11,000,000 spores. The same authority states that 

 one " shaggy mane " ( Coprinus comatusy mushroom may pro- 

 duce 5,000,000,000 spores. It is obvious that only a small 

 number of these spores succeed in producing new plants ; 

 otherwise they would very soon occupy the earth. 



246. Puffballs. One of the most important differences be- 

 tween puff balls (fig. 202) and mushrooms is that puffballs 

 produce their spores within an inclosed reproductive body 

 instead of upon gills or within pores. Puffballs may become 

 quite large, even a foot in diameter, and, when ripe, may con- 

 tinue to emit small clouds of spores intermittently for several 

 years. One giant puffball (Lycoperdon giganteum) was esti- 

 mated 1 to contain 7,000,000,000,000 spores. 



247. Classification of the thallophytes. The following is the 

 classification of the thallophytes, including the chief genera 

 that we have considered. This classification is placed here for 

 use as a general summary, and not primarily to be committed 

 to memory. If studied carefully, it will give a good review 

 of the three chapters on the groups of thallophytes. 



GROUP A. THALLOPHYTES. Since the bacteria and the blue-green algae 

 are so much alike in structure and in methods of reproduction, they are 

 classified together rather than with the fungi and algae respectively. 

 CLASS J. SCHIZOPHYTES (the fission plants) 



SUB-CLASS I. SCHIZOMYCETES (bacteria, or fission fungi). Illus- 

 trated by numerous type forms and various methods of living 

 SUB-CLASS II. SCHIZOPHYCE.E, or Cyanophyceae (the blue-green 

 algae, or the fission algae). Leading genera used as illustrations 

 Nostoc, Oscillaloria 

 CLASS II. ALG^E 



SUB-CLASS I. CHLOROPHYCE/E (the green algae). Leading genera 

 used as illustrations Pleurococcus, Spirogyra, Cladophora, 

 Vaucheria, Chara 

 SUB-CLASS II. PH^OPHYCE^: (the brown algae). Leading genera 



used as illustrations Fucus, Sargassum 



SUB-CLASS III. RHODOPHYCE^E (the red algae). Leading genus 

 used as illustration Dasya 



1 Buller, A. H. R., Researches on Fungi. Longmans, Green & Co., 1909. 



