CHRLAL CULLVALLUN aND CROPS 69 
All the temperate grains can be grown within the tropics, at an 
altitude of 6-12,000 feet. In Abyssinia, for example, oats and barley 
grow up to 12,000 feet ; maize to 9,000 feet. In Mexico, wheat and 
barley are grown on the temperate tablelands (éerras templadas) 
and in the cold mountain regions, in the latter at a height of 8,000 
feet above the sea; maize is grown everywhere at the lower 
elevations. On the Andes of Chile and Bolivia, both temperate 
and tropical grains are grown in vertical zones, barley at the high- 
est altitude, maize and rice at the lowest, wheat between. At 
10,000 feet the climate is as well adapted for the growth of the tem- 
perate grains as it is “ perfect for the European constitution.” 
The southern zone of temperate grains has for its boundaries the 
tropic of Capricorn and the 4oth parallel. 
We will now consider the distribution and cultivation of the 
cereals on each continent, taking Europe first. Barley, oats and rye 
are associated with pines and firs, and these grains reach their most 
northerly limit of culture in Scandinavia (by reason of the modify- 
ing influence which the Gulf Stream exerts upon the climate there), 
barley growing as far northas the 7oth parallel, where uninterrupted 
sunshine ripens it in 90 days; oats to 68°, wheat to 63°. In Eastern 
Russia, where the climate is strictly continental (away from sea 
influences), the northern limit of these cereals is several degrees 
lower. Oats and rye are the grains most generally cultivated 
around the lower Baltic and in the northern part of the great 
central plain (in Germany and Russia), often in association with 
barley, sometimes with wheat. Wheat is associated with deciduous 
trees, and predominates all over Middle Europe—the northern half 
of France, S.W. Germany, the plains of Lombardy and Hungary, 
and in the ‘black earth’ region of Russia between the Carpathians 
and the Ourals. Barley, oats and rye here accompany wheat in 
varying proportions. The growth of grain on the Alps ceases at 
an altitude of about 4,000 feet, but on some of the southern slopes 
rye ascends 1,500 feet higher. Maize, associated with the vine and 
olive, comes into cultivation south of the 48th parallel, at first 
sparingly, then generally ; wheat is grown everywhere in company 
with maize ; on the other hand, rye, oats, and barley become minor 
crops the more as we go southward. Lastly, rice appears in the 
evergreen zone of Southern Europe, where there is sufficient 
irrigation, viz. the south of Portugal, the low-lying parts of Spain 
on the Mediterranean, and the valleys of the Po and Lower Danube. 
Rice is associated with such fruits as figs, oranges, grapes, olives, 
and almonds, whose thriving depends upon the mildness of winter 
and the high summer temperature enjoyed by this part of Europe, 
owing to its situation on the shores of a great inland sea and to the 
protection from cold N. and E. winds afforded by the Pyrenees, 
Alps, Carpathians, and Balkans. The chief cereals of Europe are 
wheat and rye ; oats and barley come next ; maize, rice, spelt and 
millets last. The countries having the largest acreage under a 
given cereal assume the following order: wheat, Russia, France, 
Italy, Hungary ; oats, Russia, Germany, France; barley and rye, 
