1 66 



Minnesota Plant Life. 



the beech-ferns; the shield-ferns, and the bulblet-ferns recog- 

 nized by the formation on their leaves of bulbils which drop 

 off and propagate the plant. Besides these there are the little 

 brown Woodsias found upon rocks and distinguished by the 

 dry aspect of their leaves, and, in rich woods, the sensitive 

 ferns and ostrich-ferns peculiar among bracken-ferns for the 

 development of two kinds of leaves much as in the flower- 

 ing ferns. The ostrich-fern especially is a regal plant. Grow- 

 ing in damp glades of 

 the forest it spreads its 

 tall graceful fronds, out- 

 lining a green Corinthian 

 capital. In the centre 

 there spring up four or 

 five smaller feather- 

 shaped brown leaves 

 which have abandoned 

 starch-making and devote 

 themselves entirely to the 

 production of spores. 



The four-leaved water- 

 fern. Most remarkable 

 in some respects of all 

 ferns is the four-leaved 

 water-fern. It does not 

 always grow in water but 

 is found in dry creek- 

 beds at the extreme western edge of Minnesota. The plant- 

 body consists of a thread-like, creeping, branched stem from 

 which small leaves, resembling four-leaved clovers, arise. These 

 are the vegetative leaves of the plant, but the spore-producing 

 leaves are modified into capsules about the shape of an ordinary 

 bean but considerably smaller. If one of these beans is chipped 

 on the side and placed in a dish of water it will open like a clam- 

 shell and in about twenty minutes a centipede-like object, three 

 or four inches long and as thick as a crochet needle will uncoil 

 itself. It seems absolutely impossible that so large an object 

 could have been packed away inside the bean-like leaf. The 



FIG. 57. Cliff-brake. After Britton and Brown. 



