234 PLANT RELATIONS. 



temperature ; and soft, the low stature and short life not 

 involving the development of specially rigid structures for 

 support or resistance. In such conditions, as would be 

 expected, annuals are in the minority, the plants being 

 mostly perennial and geophilous. Geophilous jDlants are 

 those which have the habit of disappearing underground 

 when protection is needed. This is probably the best adap- 

 .tation for total disappearance from the surface and for rapid 

 reappearance (see §1J:3). In such conditions, also, rosette 

 forms are very common, the overlapping leaves of the rosette 

 closely pressed to the ground diminishing the loss of heat 

 by radiation. It has also been noticed that these arctic and 

 alpine carpets show intense color in their jflowers, and often 

 a remarkable size of flower in proportion to the rest of the 

 plant. Wherever the area is relatively moist, the carpet is 

 prevailingly a grass mat ; in the drier and sandier spots 

 the herbs predominate (see Fig. I'.i5). 



In the case of plants which can grow both in the low 

 ground and in the alpine region, a remarkable adaptation 

 of the plant body to the different conditions may be noted. 

 The difference in appearance is sometimes so great that it 

 is hard to realize that the two plants belong to the same 

 species (see Fig. lO(J). 



164. Meadows. — This term must be restricted to natural 

 meadow areas, and should not be confused with those arti- 

 ficial areas under the control of man, which are commonly 

 called meadows. The appearance of such an area hardly 

 needs definition, as it is a well-known mixture of grasses 

 and flowering herbs, the former usually being the pre- 

 dominant type. Such meadow-like expanses are common 

 in connection with forest areas, and it is an interesting 

 question to consider what conditions permit forest growth 

 and meadow growth side by side (see Fig. 1'.I7). 



The greatest meadows of the United States are the well- 

 known prairies, which extend from the Jlissouri eastward 

 to the forest regions of Illinois and Indiana (see Fig. 198). 



