268 THE BIOLOGY OF THE PLANT 



transfer two or three of these to a slide, and cover with 

 a glass supported by a piece of hair or a scrap of paper. 



MOEPHOLOGT 



A. — Vegetative Condition. 



I. Naked-eye characters. — Examine the plant as it 



grows in the water or on the surface of the soil. 

 Compare it with Spirogyra in mode of growth, 

 color, length of filament, etc. Does it have or- 

 gans of attachment, as roots ? Does it have the 

 slimy feel of Spirogyral Do you ever find it 

 forming a frothy scum on the surface of the 

 water ? Why ? Do the tips of the filaments 

 ever project above the surface of the water? 

 Why ? Do these tips point towards the sun or 

 away from it ? Do you find any difference in 

 the direction of the tips of filaments exposed to 

 strong su^nlight and those exposed to less intense 

 light ? Why is it called " Green Felt " ? 



II. Microscopic characters. — Examine first with a low, 



then with a high power. 



a. Shape. — What is the shape ? Is the filament sim- 

 ple or branched ? If branched, do the branches 

 originate at any particular points? What rela- 

 tion of position exists among the branches ? Does 

 it have roots ? What is the shape of the end of 

 the filament ? In what respects does this plant 

 difl'er in shape from Spirogyra ? 



h. Size. — How long is a filament ? Is its diameter 

 greater or less than that of the species of Spiro- 

 gyra examined ? Does it have the same diameter 

 throughout its entire length ? 



