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INTRODUCTION TO BOTANY 



plant is well fitted for much chlorophyll work, and conse- 

 quently abundant food manufacture. It grows with remark- 

 able rapidity. A Oladophora plant sometimes becomes broken 

 into two or more pieces, when each may grow into a new plant ; 

 or at times the cells divide and form many small swimming 



spores, each of which may grow into 

 a new plant. 1 



212. Vaucheria : habitat and struc- 

 ture. Vaucheria is commonly called 

 " green felt," a name which suggests 

 the characteristic appearance which it 

 presents as it grows upon the moist 

 surface of the earth, in pots, on grow- 

 ing tables in the greenhouse, or upon 

 damp, shaded soil out of doors. It 

 also grows in pools of water, where it 

 is distinguished from many other algse 

 by its coarseness. Certain species of 

 Cladophora are coarser than Vaucheria, 

 but their greater length and more 

 extensive branching will ordinarily 

 enable one to distinguish them. Plants 

 that have been kept in a dish of water 

 in the laboratory for a few days grow 

 into a heavy, moss-like mass and are 

 good material for study. The plant 

 branches considerably (fig. 177), and 

 the newest branches are the greenest and most active. The 

 older portions may die, thus separating the branches from 

 one another so that new individuals are formed by vegeta- 

 tive reproduction. No cross walls appear in the vegetative 

 part of the plant, and all the cells are within the tubular 

 wall of the plant. 2 



1 For details of reproduction by spore formation, see Cladophora and 

 Ulothrix in Bergen and Caldwell, Practical Botany, or Bergen and Davis, 

 Principles of Botany. 2 Such a plant is called a coenocyte. 



FIG. 176. A branching alga 

 (Cladophora) 



This plant, but a small part 

 of which is here shown, often 

 forms great mats of growth 

 which cover the rocks and 

 sticks upon which it grows. 

 After Collins 



