CHAPTER III 

 THE NORTH TEMPERATE ZONE 

 EURASIA AND NORTH AFRICA 



The line between the sub-arctic and north temperate is a very 

 ill-defined one. In western America, and western Europe, tem- 

 perate conditions prevail much further north than in Asia or 

 eastern America; but in general one may place the southern limit 

 of the sub-arctic at about 55°. 



Between this and 30°, where sub-tropical conditions begin, is a 

 vast expanse of land. Nearly all of Europe, except parts of 

 Scandinavia and Russia, lie between these latitudes, which include 

 also the Mediterranean littoral of Africa, the major part of Asia 

 south of Siberia, and practically the whole of the United States 

 and southern Canada. 



A large part of the sub-arctic flora, including all the trees, 

 extends into the temperate zone, where the pines, firs, spruces, and 

 larches; the poplars, birches, and willows, mingle with the beeches, 

 maples, oaks, and other characteristic trees of the temperate 

 zone. As all of these are represented by similar, if not identical 

 species in Eurasia and America, the forests of the higher latitudes 

 of the temperate zone have a general similarity of aspect, although 

 very few species are common to the old and new worlds. 



The same is true of many shrubs and herbaceous plants, e. g., 

 roses, honeysuckles, dogwoods, raspberries, elders, viburnums, 

 etc. ; violets, lilies, buttercups, anemones, clovers, and many other 

 familiar flowers; but there are many genera which are peculiar, 

 or much less wide-spread. Thus America has no Narcissus, snow- 

 drops, foxglove, broom or heath; while Europe has no mountain 

 laurel (Kalmia), blood-root (Sanguinaria), Pentstemon or Tril- 

 lium, and other lists could be extended indefinitely. 



These differences become more and more pronounced as we 

 proceed southward, until the differences become much more 

 pronounced than the resemblances. 



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