DISTKIBDTION OF CEREAL GRAINS. 



669 



Rye ; it is cultivated in the middle and south of France, England, 

 part of Scotland, part of Germany, Hungary, Crimea, and the 

 Caucasus. We next come to a district where wheat still abounds, 

 but no longer exclusively furnishes bread, — rice and maize becoming 

 frequent. To this zone belong Portugal, Spaia, part of France, Italy 

 and Greece, Persia, Northern India, Arabia, Egypt, the Canary 

 Islands, etc. Wheat can be reared wherever the mean temperature of 

 the summer, for a period of at least three or four months, is above 55°. 

 It succeeds best oil the limits of the sub-tropical region. In the Scan- 

 dinavian Peninsula the cultivation of Bere extends to 70° north lati- 

 tude. Eye to 67°, and Oats to 65°. The cultivation of Eice prevails 

 in Eastern and Southern Asia, and it is a common article of subsist- 

 ence in various countries bordering on the Mediterranean. Maize 

 succeeds best in the hottest and dampest parts of tropical climates. 

 It may be reared as far as 40° north and south latitude on the Ameri- 

 can continent on the' western side, while in Europe it can grow even 

 to 50° or 52° of latitude. It is now cultivated in all regions in the 

 tropical and temperate zones, which are colonised by Europeans. 

 MiUet of different kinds is met with in the hottest parts of Africa, in 

 the south of Europe, in Asia Minor, and in the East Indies. Henslow 

 gives the following table to show the range of Wheat and Barley (Bere), 

 and the mean temperature required for them : — 



Winds, water, and animals are also instrumental in disseminating 

 plants. Many seeds and fruits with winged and feathery appendages 

 are easily wafted about ; others are carried by rivers and streams, and 

 some can be transported by the ocean currents to a great distance, 

 with their germinating powers unimpaired. 



