GKBEN SLIME 41 



the needle point or a scalpel. The cover -glass may 

 then be put on and the specimen examined as usual. 



MOEPHOLOGT 



Naked-eye Charaoters : 



a. Occurrence. — In what other places than those men- 

 tioned above do you find the plant ? If found in 

 ditches, do you get it most abundantly in muddy, 

 sandy, or rocky places ? If on flower-pots, on the 

 lighted or shaded side ? If on trees, does it grow 

 better on those with rough or on those with 

 smooth bark ? Why "i Does it show preference 

 for the north, east, south, or west side ? Why ? 

 Is the film even in thickness, or do you find 

 marked variations in this respect ? 



h. Color. — What is the usual color? Are specimens 

 from different situations always of the same 

 color? If you find variations, how do you ex- 

 plain them ? Put under a tumbler or a bell-jar 

 and keep moistened a piece of dry bark bearing 

 green slime. Does the color change at all ? Put 

 into a small bottle of alcohol a piece of clean 

 bark upon which green slime is growing and 

 leave for a few hours, then remove the bark from 

 the bottle. What change, if any, has taken place 

 in the color of the green slime ? In the alcohol ? 

 Explain. 



c. Structure. — Scrape the film off a piece of dry bark. 

 Does it adhere firmly to the bark ? Does it sep- 

 arate into large or small flakes ? Do the flakes 

 hold together well, or do they break up into 

 smaU particles? Scrape a film off a piece of 



