A MANUAL OF BOTANY 113 



observe the variety of colors. Observe, in particular, tli« 

 manner of branching, and compare with that of the rockweed. 



Experiment. Wet some dried specimens and note the 

 rapidity of t\\Q fresheninrj-uj) process. Also that some forms 

 are gelatinous, or very mucilaginous. If at hand, treat Irish 

 moss in the manner suggested and observe the results. 



Drawings. Draw' i)ortions of several forms and briefly 

 describe, or take notes sufficiently full to characterize each 

 kind drawn. 



Reading. Read about the seaweeds in good reference 

 books. Why is it that these algcC do not show any green 

 color ? How can you show experimentally that the plants 

 contain chlorophyll ? Of what advantage is the red color ? 

 Find out any uses to which these plants are put by man. 



Type 13. Chara 



Habitat. The plant grows abundantly in ponds, slow 

 streams, and lakes. Very common in park ponds and lakes, 

 often causing much damage and necessitating removal. It 

 is found at all depths from six inches to twenty or more 

 feet. It is not easily grown in laboratory aquaria. 



Appearance. Examine the plant as it grows (if possible) 

 and observe its color, appearance, and direction of growth, 

 whether floating or erect. Take some between the thumb 

 and finger, rub and observe result. Smell of a fresh mass 

 of the plant. What effect or purpose may this odor have ? 

 Place some dried specimens in a vial and add diluted hydro- 

 chloric acid. AVhat do you observe ? How do you explain ? 

 What advantage to the plant may this condition of the stem 

 be? 



Parts of the plant. Trace a main axis, often called a stem, 

 throughout its length. Observe at intervals a tchorl (circle) 

 of branches, and here and there a secondary smaller axis 

 bearing similar whorls. How many branches in a whorl? 



