4/6 Minnesota Plant Life. 



thoroughworts. Occasional xeroplivtic plants enter such 

 meadows and one may find in them mulleins or scouring-rushes 

 growing among the typical mesophytic grasses and herbs. In 

 such localities plants of xerophytic tendencies may often be 

 distinguished by their rosettes of leaves. In the meadows 

 mosses and sometimes ferns occur. With the meadows should 

 be compared the broad expanses of mesophytic prairie, es- 

 pecially those of the Red river valley and the Minnesota. 



Cultivated fields. Cultivated fields and gardens, where the 

 soil is stirred by the plow or spade, come to be occupied by a 

 group of vegetation classified by the farmer as crop and weeds. 

 This is, of course, a purely economic classification, and to get 

 the proper botanical idea of a cultivated field all thought of 

 human interest in the kinds of plants that grow must be elim- 

 inated. It will then be discovered that the field is occupied 

 by a dominant formation which owes its selection and abun- 

 dance to the distribution of its seeds or fruits through human 

 agency. A number of accessory plants are also developed, in- 

 cluding a variety of common grasses and herbs. Into such 

 fields some xerophytic forms, like the purslanes, introduce 

 themselves, but the majority of the plants will not show con- 

 spicuously the xerophytic adaptations of structure which have 

 been described ; that is, the weeds of a cultivated field are not 

 predominantly silky or strong-scented, or succulent, or plants 

 with the edges of their leaves rolled in together. In such 

 localities, rather, will be found the thistles, the fox-tail grasses, 

 the oxeye daisies, the amaranths, pigweeds and wild parsleys, 

 together with some kinds of buttercups and clovers. Such a 

 field in its general composition bears a close resemblance to 

 pastures or meadows. .\ particular kind of field is produced 

 when the soil is sandy or alkaline. Or, if the soil is very hard, 

 composed of clay closely packed together, the vegetation cov- 

 ering it will be different from that of ordinary cultivated fields. 

 San<l-lo\ing ])laiUs or mat i)lants will come in and establish 

 themselves prominently along with carpctweeds, purslanes, 

 thistles and w^ild lettuce. 



Roadside vegetation. W ith such wastes of weeds as have 

 been described, roadside xegetatinn nia\ be connected and ilie 



