38 A MANUAL OS THE CONIFER^. 



Prairie Eegion of North America, and (2) — the Pampas of South 

 America. The areas of these treeless regions form in the aggregate 

 no inconsiderable portion of the whole surface of the land. 



Eeserving the statements of the separate habitats of the Tribes, 

 Genera, and the Species contained in the Order for their respective 

 Sections in Part II., the general distribution of the existing Coni- 

 ferous vegetation may bo conveniently sketched according to the 

 Natural Floras or Kegions denned by Professor Grisebach,* with 

 some necessary modifications which the subject requires. In all 

 such divisions, however, "there is a definiteness and sharpness of 

 outline which is really an inherent defect," f and in the adaptation 

 of these geographical divisions for the purpose of explaining the 

 distribution of Coniferas, this defect is occasionally manifest. We 

 commence with the Etjropeo-Sibekian region as being that which 

 includes the greater part of our own quarter of the globe, and 

 which was, within historic times, almost entirely covered with forest. 

 In this region a belt of Conifers stretches, almost unbroken, from 

 the , North Atlantic Ocean to the Sea of Ockhotsk, the belt 

 occupying the northern limits of the region and reaching in Europe 

 as far north as latitude 68° 10' N., the limit of Abies excelsa, and in 

 Asia to latitude 69°, the limit of A. obovata. This belt is composed 

 exclusively of members of the Fir and Pine Tribe. South of 

 this belt, much of the land has been cleared for cultivation, 

 especially in Europe, so that the primeval forests are chiefly restricted 

 to the mountain chains and hilly districts. On all the mountain 

 chains within the region, there is a zone of vegetation consisting 

 entirely of Coniferee, both above and below which there are Coni- 

 ferous trees and shrubs intermingled with plants of other orders, 

 their proportion to the entire vegetation of the adjacent zones 

 gradually diminishing in both directions in receding from the zone, 

 formed exclusively of Conifers. The altitude of the Coniferous zone 

 varies with the latitude in proceeding from north to south. Thus, 

 in Norway and Sweden, the Coniferous forests occupy the slopes of 

 the Scandinavian mountains from the base to the snow line. On 

 the Hartz mountains, in Germany, the Coniferous zone predominates 

 at an elevation of about 3,000 feet; on the Carpathians, at 4,000 



* Die Vegetation der Erde nach Hirer Mimatischen Anordnimg. 

 t Thom<$'s Structural Botany, p. 434, Editorial Note. 



