602 APPENDIX A 



Subphylum II. Fungi (fun' ji). The fungi are set apart from other 

 thallophytes and from nearly all higher plants in their lack of chlorophyll. 

 Not all of the various groups of fungi are closely related. In all probability 

 they originated at different times and from different groups of algae, so 

 that phylogenetically the "fungi" do not form a natural group. Func- 

 tionally they are sharply distinguished from all other plant groups by 

 their inability to manufacture food by photosynthesis. 



The Bacteria (Schizomycetes) are familiar by name to everybody. They are 

 single-celled plants which, like the blue-green algae, lack a distinct nucleus. 



*#Uxv, 7^\ 



Fig. A.4. Types of bacteria. A, spherical forms; 1, coccus; 2, streptococcus; 3, staphylococ- 

 cus; 4, Sarcina; 5, diplococcus; 6, encysted diplococci. B, bacilli without flagella; 1, various 

 forms and groupings of bacilli; 2, 3, development of endospores in various positions. C, 

 bacteria with flagella. D, forms of spirilla. E, spirochaetes. {From Hill, Overholts and Popp, 

 Botany, 2d ed.) 



According to the shapes of their cells, bacteria are spoken of as cocci (spherical), 

 bacilli (rod-shaped), spirillae (spirals), etc. All are extremely minute. 



Bacteria or their spores occur practically everywhere. The bacterial spore is 

 not a reproductive cell, since a single bacterium produces but a single spore; 

 instead it is an inactive, resistant stage adapted for dispersal and survival under 

 conditions of dryness, heat, or cold, which would be fatal to the active phase of the 

 cell. 



We are prone to think of all bacteria as noxious, and it is true that many of 

 them are parasites of animals and plants and that they include the causative 

 agents of a large number of human diseases. Far more, however, are not injurious 

 to other organisms, and a great many are beneficial, both from the standpoint 

 of their usefulness to man and because of the indispensable part they play in 

 organic cycles. We have already made mention of some of their more important 



