PLANT LIFE IN PONDS & STREAMS 



The movements of some of the free swimming, 

 that is to say non-attached Diatoms, are worthy of 

 study. The scientific name of one kind, translated 

 into everyday language, means little boats, and 

 indeed they are well named for their beautiful 

 aquatic manoeuvres rival those of any ship. 



Somewhat similar in habit to the brown Diatoms 

 are the green Desmids, but, whereas, the former also 

 occur in the sea, the latter are all confined to fresh 

 water. Sometimes Desmids are so numerous that 

 they make the pond water as green as green-pea 

 soup. It would be as impossible to descibe all these 

 plants as was the case with the Diatoms, but gener- 

 ally they may be recognised by the fact that they 

 are composed of two similar halves, separated by 

 more or less of a waist. Although some of the Des- 

 mids exhibit a certain amount of movement they 

 are not active like the Diatoms. 



Late spring and autumn are the best seasons to 

 hunt the ponds for our next object, which rejoices 

 in the name Chlamydomonas Angulosa, a good ex- 

 ample of the extraordinary fact that some of the 

 smallest animals and plants have the longest names. 

 This little plant is interesting in itself and doubly 

 so, because it was for long thought to be an animal ; 

 it is wonderfully animal-like in its movements. 

 Chlamydomonas is very minute, so we must use 

 our highest magnification when we examine it. It 

 is an oval, one-celled plant enclosed in a clear mem- 

 })rane. The green colouring matter is arranged in 

 the form of a cup, within the hollow of which is a 



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