36 Minnesota Plant Life. 



the one which produced them. This process .is rapidly repeated 

 and in a few days such a geometric progression will bring into 

 existence an enormous number. A variation of the process 

 sometimes occurs when there is an unusual abundance of mois- 

 ture, as after a heavy rain. Each of the little balls formed under 

 these circumstances is provided with a pair of extremely delicate 

 lashes by means of which it propels itself through the water 

 with a curious rotating and wabbling movement, something like 

 that of a rifle-ball, only, of course, very much slower. It takes 

 some moments to travel an inch, yet, on account of the very 

 small size of the plant, its movements viewed under a microscope 

 seem fairly agile. 



Red snow. The famous red-snow plant, which is found upon 

 mountain heights in the Alps, in Bolivia^ or in the Selkirks, is a 

 relative of the green-slime so common upon flower-pots in the 

 Minnesota conservatories. The color of the red-snow plant is 

 adapted, no doubt, to the cold region which it has chosen for 

 growth, and, in general, red coloring substances in plants have 

 been described as warining-up colors thus the autumn leaves 

 turn red not because they are dying but for very much the same 

 reason that men wear overcoats and woolens. Redness may 

 be regarded as one of the plant's ways of protecting itself against 

 a low or falling temperature. 



Water-nets. Among the bright-green algae a conspicuous 

 but not extremely common form in Minnesota is the water-net. 

 This plant grows in quiet pools and resembles very much a piece 

 of green mosquito-bar rolled up in an irregular cylinder, three 

 or four inches long, and an inch or more in diameter. Each 

 side of a mesh in the net is a joint or cell of the plant, and in 

 each cell the living contents have the power of arranging them- 

 selves into a tiny net. When the wall of an old cell dissolves 

 the tiny net begins to grow, enlarging all of its mesh-sides 

 equally, until it has become as large as its parent. Besides this 

 propagative process the water-net has the power of breeding 

 somewhat as does the pond-scum, and produces curious little 

 microscopic jackstone-shaped fused-bodies which remain dor- 

 mant at the bottom of pools during the winter months. A 

 great variety of bright-green algae are found growing upon peb- 

 bles, upon the stems of submerged vegetation and upon twigs or 



