278 



Minnesota Plant Life. 



the partition is evanescent, as in the garden radishes. Very 

 common forms are the pepper-grasses with little circular pods, 

 the shepherd's purses with heart-shaped pods, the hedge-mus- 

 tards with their long and slender pods, the rock-cresses grow- 

 ing upon cliffs and along gorges, the water-cress abundant in 

 cold streams issuing from springs, and the other cresses, some 

 in the fields, some in the woods and others in marshes or 

 swamps. In a great many of the mustards of Minnesota the 

 leaves are narrow and deeply lobed along the sides. A number 

 bear, at the surface of the ground, 

 rosettes of leaves from which the 

 slender flower-bearing axis arises. 

 The flowers are usually arranged in 

 racemes and are commonly white 

 or yellow in color, constructed on 

 the plan of four. Four sepals, four 

 petals, six stamens and two carpels, 

 united into a single pod, constitute 

 the parts of the normal mustard 

 flower. One of the smallest of the 

 land-flowering plants in Minnesota 

 is the whitlow-grass, a cress which 

 produces a tiny rosette of leaves and 

 a little stem an inch or two in 

 height, on which a few minute white 

 flowers are borne. 



Pitcher-plants. The seventeenth 

 order includes the pitcher-plants, FlG - 134 - etcher-plant. After Britton 



and Brown. 



grouped in two families, to one of 



which belongs a common Minnesota variety, and the sundews 

 and Venus' fly-traps. All of these plants are carnivorous and 

 are very remarkable for the skillful devices by which they catch 

 the insects that form a part of their food. The Venus' fly-trap, 

 which in conservatories is sometimes cultivated, from its Car- 

 olina home, is a little herb with leaves built upon the general 

 plan of a steel trap. The base of the leaf is somewhat elongated 

 and provided with wings of green tissue. Above the middle 

 there is a strong constriction, and the end of the leaf is almost 

 round, with a longitudinal rib separating it into two halves. 



