HOW TO KNOW THE FRESH-WATER ALGAE 



such as a stout chalk line for the pull cord and the leaders. Braided 

 copper wire is sometimes used for the leaders but these often become 

 so worn at the points of attachment that they snap. 



Microscopic forms of algae may be obtained in great numbers 

 from the squeezing of Sphagnum (and other mosses) especially when 

 the plants feel slippery or slimy. Small pools and seeps in Sphagnum 

 beds abound in many species of algae, especially desmids. The moss 

 or overhanging dead grass and stems of rushes can be squeezed di- 



Utricularia, an under-water animal-trapping plant, is a 

 veritable Christmas tree loaded with miscellaneous algae 

 which are caught among the leaves and held in the 

 mucilage that envelopes the plant. 



rectly into a vial, or if a gross, mass collection is desired, the moss 

 can be squeezed into the plankton net so that a concentrated puree 

 of algae is obtained. Utricularia (bladderwort), especially when it oc- 

 curs in soft water or acid lakes, is a veritable net itself and handfuls 

 of this plant can be squeezed into a plankton net with very fruitful 

 results. 



Specimens collected from the field should be put in receptacles 

 with just enough water to cover them, leaving ample space for air, 

 especially if the sample is to be stoppered for some time before arriv- 

 ing at the laboratory. Clots of larger, filamentous algae may have the 

 excess water gently squeezed from them, rolled in wet, and then in 

 dry paper (newspaper highly satisfactory) and so may be kept in 

 good condition for 24 hours or more. 



Immediately upon returning from the field, vials or packets of 

 material should be opened and poured into wide, shallow dishes so 

 that they may be well aerated. If the collection is not too crowded 

 in a dish of water the plants may be kept alive and in good condi- 



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