274 



COLLEGE BOTANY 





In rep'roduetion it forms stationary bodies of definite form 

 which, resemble fungi. These structures are characteristic of the 

 different species and are known as sporangia. They bear the 

 spores which under favorable conditions of warmth and moisture 

 give rise to ciliate, tmieellular, animal-like cells which fuse and 

 form a new multinuclear plasmodium. 



Most of the species belonging to this division are sapTO- 

 phytic, but some few are the causes of diseases of other plants. 

 The club root of the cabbage, a very important and destructive 

 disease, is due to one of these species. 



The Schizomycetes are the " fission fungi " or " bacteria." 

 They are extremely small, unicellular organisms, and are capable 



of multiplying very rapidly. They 

 are the smallest known forms of 

 life. They are very similar in 

 "j^^f structure and life history to the 

 GyanophyceoB (page 2fil), but they 

 do not contain the coloring mate- 

 rials. Some of them are sapro- 

 FiG. 124.— (a)Type3 ofmatureMyxp- phytes and others are parasites. 



mycetes; (6) and {c) stages in the devel- . 



opment of the Plasmodium. There is an euormoUs number of 



species and we see the results of their activities on every hand. 

 They live on or in the food supply which they take in through 

 any part of the cell wall by means of absorption. However, the 

 food must first undergo a change as a result of the action of en- 

 zymes which are secreted by the organista. Some require air and 

 are known as aerobic forms, while others thrive best without air 

 and are known as aiideroliic forms. Reproduction is by simple 

 fission andnnder favorable ci rcui.isitancesi s very rapid. Although 

 extremely small, they are among the most important f O'rms of life. 

 They, together with fungi, cause the souring of milk, the ripen- 

 ing of butter and cheese, and the decay of fruits, vegetables and 

 meats. There are many species which cause diseases, of which 

 some of the most common are tuberculosis, anthrax, pneumonia, 

 diphtheria, ts'phoid fever and lockjaw. There are other species 



