38G MR. M. p. PRICE ON THE VEGETATION OT? 



the Siberian town of Miunusinsk. The Sayansk mountains, which form the 

 nominal frontier between Siberia and Mongolia, are not a true range in the 

 strict sense of the word, but rather a series of disjointed uplifts, of which 

 the highest peaks reach 8000 and 9000 feet in places, and are connected by 

 numerous passes of from 4000 to 5000 feet in altitude. The trend of the 

 range is indefinite, and many spurs jut out far into the Siberian forests on 

 the north and into the plateau basin of the Bei Kem on the south. The 

 average height of the floor of the basin is roughly between 2000 and 3000 

 feet, and it is thus everywhere surrounded, except at the point where the 

 Ulu Kem bursts through the Sayansk mountains in a series of gorges and 

 rapids, by a complete range of encircling mountains. To the south lie the 

 Tannu-ola range, a complete barrier between the Yenisei basin and the 

 North-West Mongolian plateau. 



The plains of the Siberian lowlands at Minnusinsk average about 900 feet 

 in altitude, and going southwards from here the traveller rises on to the first 

 step of the Central Asiatic plateau, which is formed by the northern spurs of 

 the Sayansk mountain system. This first step of the plateau is clothed on its 

 northern slopes with dense forests, which in their floral type show aflinity to 

 the sub-arctic forest of Siberia some 400 miles to the north. The latter lies 

 between the latitudes of 56° and 72°, and nowhere rises above 600 feet above 

 the level of the sea. Similar conditions, however, are found on the Sayansk 

 mountains between latitudes 52° and 54° at heights varying from 3000 to 

 5000 feet. Thus the same vegetations are found in northern latitudes at low 

 altitudes, as in southern latitudes at higher altitudes. In other words altitude 

 compensates for latitude. Between the sub-arctic forest belt of Central 

 Siberia and the forests of the Sayansk mountains lie the steps of Minnusinsk 

 and Abakansk in the Minnusinsk Government of Siberia. Here the dry 

 steppe-like vegetation of Central Asia seems to have pushed its way in as a 

 wedge between what may at one time have been a continuous zone of sub- 

 arctic forest. As the glaciers retreated northwards a steppe-like vegetation 

 crept evidently into the Siberian lowlands, which lie in southern latitudes 

 and have thus effectively isolated the floral system of the Sayansk. 



In the Upper Yenisei plateau, besides the sub-arctic forest and a flora 

 characteristic of northern Siberia, there is also the Siberian Larch forest with 

 an accompanying floral association. The former prevails in a long strip 

 along the north or Siberian side of the Sayansk system and in all the higher 

 parts of the plateau where the winter is long and severe. The Larch forest 

 on the other hand, prevails in the lower altitudes and is indicative of a drier 

 climatic condition. For in winter snow lies less deeply in the more southern 

 latitudes and on the lower altitudes of the Upper Yenisei plateau, than on 

 the northern slopes of the Sayansk. In the former places the summer rain- 

 fall is only assured by numerous sharp thunder-storms. 



