334 Minnesota Plant Life. 



water-purslane, but resemble the latter variety in general char- 

 acters. One variety of Ammania occurs in the state, and it 

 may be recognized by the opposite linear leaves, with clasp- 

 ing bases and sharp tips. From one to five flowers, the petals 

 of which soon fall from the bell-shaped calyx, are produced 

 in the axils of each leaf. In the water-purslane the flowers 

 are solitary in the axils of the tiny, opposite, slender leaves 

 and are very small, green and inconspicuous. The Rotala 

 resembles an Ammania in its larger size, varying from two to 

 six inches in height, but has the small axillary flowers of the 

 water-purslane. Unlike those of the water-purslane, they are 

 furnished with four small petals between the four lobes of the 

 bell-shaped calyx. The swamp loosestrife, which occurs in the 

 St. Croix valley, has stems from three feet to ten feet in length 

 and with whorls of willow-shaped leaves. The flowers are 

 nearly an inch in breadth and are clustered in purple cymes 

 in the axils of the whorled leaves. The Ly thrum, or purple 

 loosestrife, is a plant of low moist ground, with alternate, stem- 

 less, lance-shaped or oblong pointed leaves and purple flowers, 

 solitary in the upper axils. These plants are not uncommon 

 along low lake shores throughout the southern part of the 

 state. A most remarkable peculiarity of the loosestrifes is 

 the formation of very extraordinary structures in the cells of 

 the outer seed-coats. In some of the varieties each cell of the 

 layer which makes up the surface of the seed is provided with 

 a curious cork-screw-like apparatus, developed in its cavity and 

 capable of being turned out into the ground, where, together 

 with hundreds of other bodies of the same nature, it assists in 

 drawing the seed into the soil. 



Evening-primroses and fireweeds. The evening-primroses 

 the family to which the cultivated fuchsia belongs include 

 two species, known as false loosestrifes, from their resem- 

 blance to the true water-purslanes. They have the same op- 

 posite leaves, axillary flowers and general habits of growth. 

 There are, however, four stamens, and capsules with four com- 

 partments instead of two. These false loosestrifes are rather 

 unusual plants of ditches, swamps and muddy banks in the 

 southern part of the state. To the evening-primrose family 

 belongs also the fireweed or willow-herb, abundant in two va- 



