APPENDIX I. 

 DIRECTIONS FOR LABORATORY STUDY. 



Part I: Morphology. 



I. ALG^E. 

 A. PLEUROCOCCUS 



i. Examine with a lens pieces of bark bearing Pleurococcus 

 and similar algae. Note the irregular distribution of the green 

 granular heaps of plants. Is there any similarity to the distri- 

 bution of higher plants over uncultivated areas? 



2. After soaking a piece of bark for a few minutes, scrape off 

 with the nail or a dull knife blade some of the green material, 

 spread it as well as possible in a drop of water on a slip of glass, 

 cover it with a piece of thin glass, avoiding air-bubbles, and 

 examine with a lens. Observe the minuteness of some of the 

 specks, which are mostly single plants. The larger ones are 

 clusters of plants. 



3. Demonstration. Examine slide under a high power and 

 observe the form and color of single plants. Notice many con- 

 sisting of two or more cells still joined together, resulting from 

 cell division. (Tf 19, fig. 18.) 



B. NOSTOC or RIVULARIA. 



1. Observe the size and form of the colonies, and the consist- 

 ence of the jelly enclosing them, (^f 13.) 



2. Crush a bit of a Nostoc colony or a whole one of Rivularia 

 between two glass slips, remove the upper slip, cover with water 

 and observe the coiled (Nostoc) or radiating straight filaments 

 (Rivularia) embedded in the jelly. (Figs. 13, 14.) 



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