Minnesota Plant Life. 



227 



Yams. A single species of yam is common in woods through- 

 out the southern part of Minnesota. The body of the plant is 

 herbaceous or slightly woody. Underground rootstocks are 

 produced from which slender twining vine-like stems arise, 

 bearing heart-shaped broad leaves with elongated pointed tips. 

 The flowers are small and borne in elongated clusters. When 

 the plant fruits, deeply three-furrowed papery capsules are 

 formed in each of which from three to six very flat thin seeds 

 are enclosed. The rootstock is fleshy and some of the tropical 

 varieties are of commercial value as articles of food. The sweet 

 potato, sometimes confused with the yam, is an entirely differ- 

 ent plant. 



Blue flags. 

 In Minnesota 

 the iris family 

 includes three 

 species. O n e, 

 the blue flag or 

 iris or fleur-de- 

 lis, is a familiar 

 object in swales 

 and mar s h e s 

 and is common 

 throughout the 

 state. The 



large blue flowers are borne on erect steins with leaves similar 

 in appearance to those of the cat-tail. The stems arise from 

 woody tuberous rootstocks. The three-celled ovary matures 

 into a capsular fruit in which the seeds are very much flattened 

 by mutual pressure. 



Blue-eyed grasses. The other plants of the iris family are 

 known as blue-eyed grasses. Of these, two species, by some 

 botanists combined into one, occur in Minnesota. They are 

 but diminutive blue flags, being tufted grass-like plants with 

 small blue flowers about a quarter of an inch in diameter. They 

 are to be found in meadows and upon wooded slopes. 



Star-grasses. One species of star-grass is fairly common in 

 the southern part of Minnesota. In general appearance it is 

 grass-like with a swollen solid bulb of rather oblong shape 



FIG. 102. Stream-side vegetation. Blue flags in foreground. 

 After photograph by Williams. 



