PLEUROCOCCUS. 



PLEUROCOCCUS is a unicellular plant, growing on damp 

 stones or ground, and is very common upon the trunks of 

 trees. 



I. Morphology. 



1. General Structure. Note the appearance of Pleuro- 

 coccus in its natural growth on a piece of bark or damp wood. 

 Is it evenly distributed over the surface? Compare several 

 specimens of bark on this point. What is the color? Does 

 it vary in different specimens? Compare pieces of dry bark, 

 and those which have been in a moist place for several days. 



2. Minute Structure. Scrape bits of the plant from the 

 bark and mount on a slide with water. Examine first 

 with the low power, arid then with the high power of the 

 microscope. Note the form of the cells, and whether they 

 are single or associated in definite groups. Make drawings 

 of any different appearances found. 



Is there a cell wall? What is its color? Can the proto- 

 plasm be seen? The green color of the plant is due to the 

 presence of chlorophyll; usually this is distributed through- 

 out the protoplasm, though it may be in several distinct 

 chloroplasts or chlorophyll bodies. Is there any nucleus 

 which can be seen in the living cells? 



n. Reproduction. 



Look for cells which are in the process of division to form 

 groups of two, three, four or more cells. This is the ordinary 



