164 



Minnesota Plant Life. 



b}' all who frc(|uciit llie woods. Of true ferns there are nine 

 families, only four of which are represented in Minnesota. 

 The filmy ferns, the tree-ferns, the forking ferns, the twining 

 ferns and the Borneo ferns are not represented by plants in- 

 digenous to the state. The families present are the bracken- 

 ferns and their various allies, the flowering ferns, the floating 



ferns and the four-leaved water- 

 ferns. Of these the lowest in type 

 are the flowering ferns, three spe- 

 cies of wdijch occur in Minnesota. 

 One of them, known as the inter- 

 rupted fern, is a common plant, 

 presenting a peculiar appearance as 

 if somewhere near the middle of the 

 large leaf two or three leaflets had 

 s]iri\-elcd. 'i'hese leaflets, unlike 



I'l«. .it A <)iiill«<)rt plant. Aflci At- 

 kinson. 



I-'k;. .t5. Clayton'.s or intfrrupttd fern. After 

 Hritton and Hrown. 



the rest, have a brown and withered look. If examined closely 

 it will be discovered that this is due to their being covered with 

 spore-cases of a brown color, while the rest of the leaflets pro- 

 duce no sj)ore-cases whatever. Another fern of this family is 

 the i-inn;inion fern which fornw leaves of two sorts, some 



