THE STUDY OF THE ALG/E. 

 By JosepJiine E. Til den. 



THE group of algae include the oldest, the lowest, the smallest, 

 and the most widely distributed forms of plant life, and yet, 

 contrary to what might be expected, they are perhaps the 

 least understood and the most generally unnoticed of any por- 

 tion of the vegetable kingdom. 



The unicellular algae form the main trunk from which at different 

 points spring the fungi, the red sea-weeds and the flowering plants. 

 Each of these branches becomes specialized along certain lines, each 

 group attaining great perfection in some characters at the expense of 

 others, so that there comes to be the widest difference in the higher 

 forms, as may be seen by comparing pod-scum with the toad-stool and 

 the rose. The relationships of the different groups have been traced 

 only by painstaking and long-continued study by many investigators. 



The varied habitation of these plants is most interesting. They 

 may be said to be almost omnipresent, for they comprise not only 

 fresh-water and marine, but also aerial and subterranean forms. They 

 flourish abundantly in the tropics and at the same time are the last 

 form of vegetation met with in the Arctic seas and give rise to the 

 phenomenon of "red snow " in Alpine regions. As fossils they are 

 present in different strata far below the surface of the earth and they 

 live at a greater depth in the ocean than any other form of plant life. 

 At the same time they exist in immense quantities in the atmosphere, 

 but are only conspicuous in the form of "dust showers" and "blood 

 rain." They thrive with equal vigor in the frozen oceans of the 

 North and the boiling waters of geysers. They seem able to endure 

 everything with the one exception of dryness. 



In size the algae range from forms that can be seen only with the 

 highest powers of the microscope to gigantic sea-weeds of Antarctic 

 regions extending several hundred feet in length. The fresh-water 

 algae seldom do more than to form a coating or fringe upon wet rocks 

 or a scum on the surface of water, thus making themselves to a casual 

 observer an inconspicuous part of the landscape. But to the initiated 

 they so increase in apparent importance that mountains and rivers 

 sink into insignificance as the botanist wades into a muddy pool to 

 capture a bit of green substance which dangles from a dead leaf and 

 he thinks may be " something new." 



When once the attention has been called to it one is impressed 

 with the abundance of algal life everywhere. The green color noticed 

 on damp sidewalks and walls is due to the presence of a one-celled 



