ARID AGRICULTURE. 



233 



PLANTS 

 NATURALLY 

 ADAPT 

 THEMSELVES 



EPPECT OP 

 CLIMATE 



Adaptation to environment and natural se- 

 lection has made profound changes in plants. 

 This is evidenced both by cultural varieties, 

 which have improved under domestication with- 

 out any special attempt on the part of man to 

 make them better, and, as well, by the fact that 

 every climatic region displays true character in 

 its vegetation, due to the plants having adapted 

 themselves to conditions. Xature alone has 

 shortened the season of certain plants, so they 

 can reproduce themselves in the colder climate ; 

 has reduced the leaf surfaces and thickened the 

 epidermis that species may be enured to 

 drought; changed the sensitiveness of plants to 

 the effects of frost or heat; and has done manv 

 other tilings to produce the marked variations 

 found in plant communities of different regions. 



Tn the Michigan Agricultural Report for 

 1880, Dr. W. T. Beal states that he found that 

 field corn becomes marked with dents in three 

 years when taken from Michigan to Kansas. On 

 the contrary, at Lansing, Michigan, dent corn 

 has a tendency to ripen earlier and become 

 r< .nnded at the tip of the kernel, from year to 

 year, unless care is taken to select seed to per- 

 petuate the dent character. A statement is made 

 in Encyclopedia Britannica that "A single ear 

 of precocious rice has given rise to the only kind 

 that can now be grown north of the Great Wall 

 in China." These statements have reference to 



