E. V. Wulff —78— Historical Plant Geography 



as first proposed by Scandinavian botanists, as pseudo-relic and the 

 species themselves, in relation to the floras into which they have pene- 

 trated, as pseudo-relics. However, in their initial habitats these species 

 remain true relics. Thus, V. I. Krechetovich (1938) cites a number 

 of species of the genus Carex having discontinuous areas, one part 

 lying in northern latitudes and the other in the south in the mountains 

 of the Caucasus and Central Asia. These species, in their southern 

 habitats, he regards as pseudo-relics that became isolated on secondary 

 post-glacial territories as a result of migration beyond the limits of the 

 glaciers. This, however, is not the only meaning of a pseudo-relic; 

 this term may also be applied in those cases when a present-day species 

 acquires the apparent character of a relic. 



Relic species under modern conditions are usually characterized by 

 conservatism, by adaptation only to specific habitat conditions, in con- 

 sequence of which they do not ordinarily expand their area or, if so, 

 only to an inconsiderable extent. 



A relic species, in case it finds itself in disharmony with present- 

 day habitat conditions and occupies a contracting area, loses its ca- 

 pacity for variation and adaptation, and, hence, is in the process of 

 becoming extinct. But, if it should chance upon favorable conditions, 

 it may be restored to its normal state and give rise to new, poly- 

 morphic forms. Consequently, a relic species of economic value, upon 

 being introduced by man into cultivation and transferred into an area 

 potentially favorable, may become an economically valuable crop 

 plant. 



True relics, which have acquired their relic character as a result of 

 natural causes, should not be confused with species that are becoming 

 extinct due to the activities of man. Such species preserved from 

 man's destruction are not true relics (unless, of course, they were relic 

 prior to man's destructive activities); they may be called anthropogenic 

 relics (cultivated relics, according to Thellung). Examples of such relics 

 are the wild einkorn, Triticum spontanum Flaksb., and the wild emmer, 

 T. dicoccoides. Ancient cultivated species, whose sown area, due to 

 their low economic value, has been reduced to a minimum and which 

 have been preserved only in a few localities, such as cultivated einkorn 

 and emmer {T. monococcum and T. dicoccum), gourds {Lagenaria vul- 

 garis), and others, may be called cultivated relics. 



The chief factors in the origin of a relic area are, thus, changes 

 occurring naturally, without the interference of man, in the habitat 

 conditions within this area. On the basis of the fact that such changes 

 may occur as a result of various causes, Schroter (1934) distinguishes 

 three types of relics. The first he calls formation relics; these occupy 

 limited areas within the boundaries of formations that have undergone 

 considerable changes in their composition. For instance, the birch and 

 Juniperus foetidissima within the limits of the beech district of the 

 Crimea are both formation relics, but they differ in age, the juniper 

 undoubtedly being a remnant of a formation occupying this territory 

 during the Tertiary period, while the birch entered into the composition 

 of the vegetation which replaced the Tertiary flora during the Ice Age. 

 At the present time the birch grows in the Crimea only on a greatly 

 restricted area to the number of a few hundred trees, whereas in former 



