THE CONTINENTAL FLORA OF SOUTH SWEDEN 363 



Accordingly, in descriptions of the vegetation of these regions the vegetation 

 of the river-banks takes a prominent place. The following works, amongst 

 many others, may be cited: Cajander 1908; Fedtshenko 1897; Flerov 1902 



(s- g- PP- 54' 5^' ^°3 — -°5' ^^^ — ^^3' ^74' ^^0 ^"*^' 1910. [This substan- 

 tial work on the vegetation along the river Oka contains a large number of lists 

 of species from riverside meadows and some photographs of them, which give a 

 good idea of the wealth of herbs found in the meadows, e. g. Plates 6, 22 and 

 26]; Komarov 1896; Kuznecov 1888 and 1901; Pohle 1903. 



In the south of Russia the differences of level of water in the rivers are con- 

 siderably greater (2 — 3 meters in the middle Volga). If the shores are flattish, 

 therefore, the regions liable to floods are very extensive. During a great part 

 of the year, however, they are very dry, and consequently the vegetation has a 

 highly xerophilous character: it is steppe-like and has many species in common 

 with the steppes. Thus the flora of the flood-regions in South Russia is of a 

 different character from those in the centre and north of Russia. See, for in- 

 stance, Busch 1888; Kuznecov 1901; Paczoski 1890 (pp. 74 ff.), 1904; Savenkov 

 1910; Korshinsky 1888; Krassnov 1887, 1889; Taliev and Vojnovsky 1902. 



Lists of species from the flood-meadows of middle Russia do not contain very 

 many species which are foreign to Central Europe and the south of Scandinavia. 

 We meet with species that are purely P^ast European ones, it is true, but the 

 bulk of them are well known to us. It is, roughly speaking, the species of our 

 own luxuriant cultivated meadows with their wealth of herbs that we meet again. 

 It may specially be pointed out that such important constituents of our cul- 

 tivated meadows as Alopecurus pratensis, P^estuca pratensis and Phleum pratense 

 form very important elements in these flood-meadows. 



It is quite natural that the flood-meadow species with a continental distribution 

 that belong- to the flora of South Sweden should be highly favoured by, and 

 dependent on, human intervention. 



Many species which in South Sweden have undoubtedly been introduced and 

 spread more widely by the hand of man grow more or less commonly in the 

 flood-meadows of central Russia, where some of them at least probably have a 

 natural abode, such as Bromus inermis, Bunias orientalis. Campanula patula, 

 Cichorium intybus. Euphorbia virgata. Geranium pratense, Alelandrium album, 

 Melilotus albus. Polygonum bistorta, Symphytum officinale. 



Ononis arvensis is a species belonging to this group which has mainly to 

 thank human intervention for its great distribution in the south of Scandinavia, 

 but which perhaps may also have spontaneous occurrences there. Here I am 

 thinking chiefly of Oland and Gotland (Plate 19). In the east of Europe this 

 species has its main distribution in the steppe regions, where it principally be- 

 longs to the flora of the flood-meadows. 



