nnesota Plant Life. 29 



end of one's finger. Usually these fruit-bodies are seen in clus- 

 ters of a dozen or more. If one of them is cut into it will be 

 discovered that the interior consists of a brown moist powder, 

 which when dry blows away in an impalpable dust. In a single 

 fruit-body such as one of these, millions of spores originate 

 which, washed away by the rains or blown about through the 

 atmosphere, may fall upon suitable decaying substances, open 

 and liberate each its tiny bit of living jelly that by itself or with 

 the assistance of others gradually builds up a new r plant-body. 



Algae. The plants known as algae secure their best develop- 

 ment in the sea, where under the name of sea-weeds they are 

 universally known and many of them admired for their beauty 

 of color and gracefulness of form. Of the algae there are five 

 principal groups; i, bacteria; 2, blue-green algae; 3, bright- 

 green algae; 4, brown algae; 5, red algae. The red algae and 

 brown algae are chiefly marine, although a few varieties of at 

 least the red group are found in the fresh w r aters of Minnesota. 

 Most of the algae in fresh waters belong to the blue-green or 

 bright-green groups, while those lowly and most extraordinary 

 of plants, the bacteria, are of such various occurrence in soil, 

 water, air, and the bodies of other organisms that I shall con- 

 sider them in a special chapter. 



Blue-green algae. The plants of this group may generally 

 be recognized by their bluish-green color, approaching some- 

 times the hue' of verdigris and never the pure grass-green which 

 distinguishes the bright-green group. One of the most com- 

 mon of them is the so-called "water flower" which in summer 

 develops in such vast quantities in the lakes of Minnesota. The 

 tiny, bluish, jelly-ball of the water-flower, ordinarily not larger 

 than a pin-head, if examined closely will be found to have a bub- 

 ble of gas at the centre, by means of which it floats. If this 

 bubble is analyzed by chemical methods it will be ascertained to 

 be more highly oxygenized than the atmosphere. It is pro- 

 duced by the growth-activities of the plant and incidentally 

 serves the important purpose of keeping it near the surface of 

 the water where it may obtain the light. At Lake of the Woods 

 I have seen these plants in such enormous numbers that the 

 water looked more like green paint than lake-water and at Lake 

 Minnetonka the cottagers often complain of the abundance of 



