Minnesota Plant Life. 



201 



rare. They should be sought in rather moist peat-bogs or in 

 marshes at the edges of lakes. 



Water-plantains and arrowheads. A fourth family includes 

 the water-plantains, the arrowheads and a few related plants 

 in which the flowers are similar though the leaves are of differ- 

 ent appearance. The common water-plantain is known by its 

 large oval leaves, two or three inches in length and with several 

 strong longitudinal ribs. The flowering stem is much branched, 

 bearing a number of pretty flowers each with three round white 

 petals, from six to nine stamens and usually several separate 



FIG. 79. Evening scene in Minnesota. Arrowheads, bulrushes and willows in foreground. 

 After photograph by Williams. 



carpels which form, as the structure matures, a little fruit- 

 cluster. The embryo in the seed is curved like a horse-shoe 

 and there is no albumen. These plants produce large masses 

 or colonies in favorable localities. They are abundant in ditches 

 and pools and along railway tracks, as well as in pond margins 

 and in marshes, but they do not commonly occur in peat-bogs 

 or tamarack swamps, except at the edges. 



Related to the water-plantains are the arrowheads, plants of 

 similar habitats and generally to be distinguished by their broad 

 leaves, shaped like spear-heads. The arrowheads, like the 

 pondw 7 eeds, frequently put forth two kinds of leaves, and if a 



