Minnesota Plant Life. 



413 



others they are more nearly entire. The root-leaves in all 

 instances, with perhaps one or two slight exceptions, differ in 

 appearance from the leaves on the flowering stems and are gen- 

 erally larger. 



The burdocks are herbs with very large ovate leaves, cottony 

 on the under side, but becoming dark green above. Two 

 varieties occur in Minnesota, the large burdock and the small. 

 The flowering heads in each are surrounded with involucres, 

 the scales of which become hooked at the end and barbed so 

 that the whole flower head separates when in fruit and is dis- 

 tributed on the fur of animals. 

 The seedlings of the burdock 

 spring up, therefore, in little clus- 

 ters, one from each of the numer- 

 ous enclosed fruits. Both species 

 are locally known as "wild pie- 

 plant" on account of their large 

 leaves like those of the rhubarb. 



Thistles are stout herbs of 

 wand-like habit, often ten feet or 

 more in height and with hand- 

 some heads made up of pink or 

 purple tubular flowers. The foli- 

 age and the involucre is pro- 

 tected by spines and the fruits 

 are provided with abundant pap- 

 pus, sometimes of plumy and 

 sometimes of hair-like bristles. FIG. 208. prairie cone-flower. After Brit- 

 Related to the thistles is the 

 bachelor's-button or corn-flower, 

 flowers of a head are not strap-shaped, but are overgrown 

 tubular flowers, blue or purple in color. 



Summary statement. There have now been passed in re- 

 view a considerable number of Minnesota plants, sufficient to 

 illustrate all the important groups. The lower groups are 

 marked by relative simplicity of structure, increasing in com- 

 plexity to the highest. Such plants as the thistles and sunflow- 

 ers occupy in the plant kingdom a position similar to that of 

 man in the animal kingdom. Structurally they are the most 



ton and Brown. 



In this variety the marginal 



