274 THE BIOLOGY OF THE PLANT 



per cent, glycerine, metric scale, scalpel, and chromic 

 acid. 



Method of Examination. — Eirst examine the plants as 

 they grow in a mass in the pond or aquarium, then care- 

 fully remove a plant from the tangle without breaking 

 any parts, and study its gross anatomy by floating it in 

 a dish of water, if the plant be living, or in fifty per 

 cent, alcohol if the specimen has been preserved. 



MOEPHOLOGT 



Nahed-eye Characters. 



a. General appearance. — Note the plant as it grows 



in the pond or aquarium. What is the color of 

 the mass ? Is the mass dense or loose ? Lift a 

 handful. Is it heavy or light ? How does the 

 plant feel to the touch? Compare with Spiro- 

 gyra and Vaucheria in this respect. Can you sug- 

 gest any reasons why the plant should be named 

 " Stonewort " ? Does it grow up to the surface of 

 the water 1 If so, does it rise and fall with the 

 water, or are the lower portions strong enough 

 to support the upper portions of the plant? Or, 

 does Chara, like various twining plants — e. g., 

 the morning-glory — depend upon other plants 

 or upon some artificial support to hold it up? 

 What is there about the aquatic habits of this 

 plant which will explain its mode of growth? 

 Can you detect any peculiar odor about Chara ? 

 If so, is it the odor of the water or of the plant ? 



b. Shape. — Carefully separate from the mass a single 



plant and float it in a dish of water. What is 

 its general shape ? Can you plainly distinguish a 



