92 LABOKATOKY AND FIELD EXERCISES 



MOLDS 

 GENERAL NATURE OF MOLDS 



Examine molds growing on various substances in the labora- 

 tory and note the following points regarding their habitat, habit, 

 and general structure : 



1. Habitat. Upon what kinds of substances do molds grow ? 



Are these substances sweet or sour ? acid or alkaline ? 

 solid or liquid ? How would the income and outgo of 

 molds in the form of gases, liquids, and solids compare 

 with that of a green plant like Protococcus or a Gera- 

 nium ? Do molds differ in the above particulars ? Com- 

 pare the income and outgo of a mold on bread with 

 that of yeast and Protococcus. Be able to point out 

 similarities and differences in the habitats, and in the 

 substances derived from them, in the three cases cited. 



2. Habit. Is a mold plant on bread or apples differentiated 



into organs or tissues like a higher plant ? See Figs. 139 

 and 140 of the text. Do different species of molds show 

 differences in color or structure ? To what great group 

 of green plants are molds most nearly related in their 

 general structure and differentiation ? In what impor- 

 tant respect do they differ from this plant group ? 



3. Gross structure and growth. 



a. G-rowth (use hand lens). Examine patches of mold on 



apples, bread, and other media with naked eye and 

 hand lens. Do the patches of mold observed seem to 

 have any definite method of .spreading by growth ? 

 Can you account for the circular appearance (Fig. 143 

 of text) often observed in patches of mold ? Are some 

 patches colored ? Where is the colored portion ? 



b. Eemove some of the colored and colorless portions of 



different kinds of molds to different slides and mount 



