38 Minnesota Plant Life. 



character of their filaments and their breeding habits remind 

 one in some respects of the sphere-alga, for they form true eggs 

 and spermatozoids. 



Bass-weeds. Of all the algae of Minnesota, the largest and 

 most conspicuous are the bass-weeds. These plants are familiar 

 to fishermen because tufts of them are commonly entangled by 

 trolling-hooks which have been dragging along the bottom out- 

 side the bulrushes. The bass-weeds have stems the thickness 

 of a knitting needle, with distinct nodes and internodes. Upon 

 the nodes whorls of branches are produced and upon the 

 l)ranches subsidiary leaflets. The whole plant, in the more 

 common form, is encrusted with a limestone deposit, which 

 gives it a brittle and stony feeling to the touch. Hence these 

 plants are also called stone-zvorts. Many of them have the habit 

 of forming diminutive bulbs which separate and serve to propa- 

 gate the plant, and they also produce near the bases of their 

 leaflets very definite oval, brown eggs, not much larger than a 

 pin-point and inclosed in a little spirally twisted jacket of cells 

 leaving an opening at the top through which the spermatozoids 

 can enter. The spermatozoids are derived from curious little 

 spherical organs of a reddish color, and each spermary, not 

 larger than a small pin-head, forms as many as 30,000 actively 

 moving spermatozoids, thousands of which are destined to be 

 lost in the water, but enough are produced so that the eggs are 

 reasonably certain of fecundation and may then, after a dormant 

 period which extends over the winter months, develop into new 

 bass-weed plants. During the cold weather the eggs and many 

 of the propagative bulbils lie safely at the bottom of the lake too 

 deep to be injured by the frosts. 



Some varieties of bass-weeds, slenderer than the others, are 

 not provided with the limestone sheath which characterizes the 

 more common form, but may be recognized by their general 

 similarity of structure. When taken out of the water they are 

 limp, though not slimy like the pond-scums. Bass-weeds form 

 an extremely abundant vegetation, generally distributing them- 

 selves in the deeper waters of a lake, outside the zone of pond- 

 weeds, or of bulrushes. Sometimes they are very common in 

 shallow waters, and I have seen them in Glenwood lake, and in 

 some of the northern lakes of Minnesota, growing vigorously 

 in water only a few inches deep. 



