E. V. Wulff —208— Historical Plant Geography 



eastern boundary at Lake Baikal; others, on the other hand, consider 

 it to be the Urals. In our opinion, neither boundary is in accord with 

 the concept of "pontic element" in Kerner's sense. Representatives 

 of this element found far to the east do not constitute there a basic 

 element of the flora but merely inclusions or penetrants (in Eig's sense) 

 within the region of entirely different basic elements. 



But not only did there arise disagreements £is to the boundaries of 

 distribution of the pontic element but the term itself was misused by 

 giving it not a geographical meaning, as Keener had in mind, but an 

 ecological. "Pontic elements" began to be used for steppe plants in 

 general, xerophytes, etc. In view of the confusion that developed with 

 respect to this term, Braxtn-Blanquet (1923) proposed to discard it 

 altogether and to substitute the term Sarmatian element. However, 

 both terms were used in various senses, so that the confusion became 

 even greater. For this reason it seems advisable to retain the term 

 "pontic element" and abandon "Sarmatian element". 



Considerable confusion was hkewise introduced by Drxjde (1890) 

 and later by Hayek (1923), who divided the pontic flora into two 

 branches, the west-pontic forest flora and the east-pontic steppe flora. 

 To the former they referred the forest flora of Central Europe, which 

 constitutes a remnant of a Tertiary flora that survived the Ice Age in 

 sheltered retreats and then returned to its former habitats; to the 

 latter, primarily steppe plants distributed from the shores of the Black 

 Sea westward over the lowlands of western Europe, which during the 

 Tertiary period lay under the sea. The pontic element actually com- 

 prises forest species, since within the limits of the main area of this 

 element there are patches of forest, the species of which cannot be 

 excluded from this element; nevertheless, to refer to the pontic type a 

 purely forest flora is a perversion of the original meaning of this term 

 that only adds confusion to its use. 



In our opinion Steffen, in the work already cited (1935), has given 

 the most correct analysis of this element. He subdivides the pontic 

 region into two provinces, the eu-pontic and the panonic (the latter 

 term was first introduced by Kerner, who referred to the panonic 

 element the steppe species of Rumania and Hungary), characterized by 

 corresponding floral elements. Having made a thorough analysis of the 

 species growing in the territory of the pontic region, Steffen found a 

 number of groups of species that could not be referred to the pontic 

 element. These include: first, wides distributed in several floral re- 

 gions; second, species distributed as far east as eastern Siberia; third, 

 pontic-Mediterranean species; fourth, species distributed from the 

 Mediterranean Basin as far as Siberia; and, lastly, plant links — Aral- 

 Caspian and pontic-Caucasian (Transcaucasian). 



To this pontic element there has been joined as subelements a num- 

 ber of other elements, which should rather be regarded as independent 

 elements or as plant links. Among such we may mention the lUyrian, 

 to which are referred species of the northern part of the Balkan Penin- 

 sula, and the Aquilonarian. The latter term was first introduced by 

 Kerner (1888), who used it to embrace species distributed not only 

 within the limits of the pontic flora but also in the Mediterranean 

 Basin: Spain, islands of the Mediterranean, occasional stations in 



