214 EMIL HADAC 



define its different components, especially the old ones. Only detailed world 

 monographs of whole genera, their cytotaxonomy and ecology combined with 

 a solid paleogeographic knowledge will throw a clear light onto the origin of 

 the Arctic species. 



To get at least some information I have analysed here the flora of Spits- 

 bergen by mapping the distribution of all its vascular plant species. I found 

 several types of distribution, which can be applied also for other parts of the 

 Arctic, but these cover only a part of the whole Arctic flora components. 

 Since there are some serious changes from some of the categories which I 

 published in 1960, I shah repeat here all the groups of the Spitsbergen flora 

 (used in our considerations above) and try to explain their characteristic 

 distribution (cf. Hadac, 1960). 



1. THE CIRCUMPOLAR OREOPHYTIC-ARCTIC GROUP 



(I prefer to use the term oreophytic, i.e. mountain type, rather than "alpine", 

 to avoid confusion with plants growing in the Alps.) The species of this 

 group occur in all the Arctic as well as in the mountains of Eurasia and 

 America. Some of them reach even the mountains of the Southern 

 Hemisphere. 



They certainly belong to the "Eoarctic" component, but it is difficult to say 

 where their place of origin is found. It could be in some of the mountain 

 ranges of Asia or North America, but also some place in the Arctic itself. 

 Anyway, they must have been relatively old, "mature" species already at the 

 end of the Pliocene. During the Pleistocene they had good opportunities of 

 spreading over all the Arctic as well as into very distant mountain ridges 

 They have persisted in different refugia during the whole of the Pleistocene. 



To this group belong, among others, Equisetum variegatum, Cystopteris 

 Dickieana, Woodsia glabella, Eriophorum Scheuchzeri, Carex rupestris, 

 Kobresia can'ciiia, Juncus triglumis, Oxyria digyria, Bistorta vivipara, 

 Saxijraga oppositifolia and several others. The last three species were found 

 in Rissian deposits in Poland by Srodoii (1954). 



Some of the species which I previously grouped in this element, due to a 

 more accurate taxonomic investigation now appear to belong elsewhere. 

 Thus, Empetnim hermaphroditum Hagerup (or E. Eamesii Fern. & Wiegand 

 ssp. hermaphroditum D. Love) appears to have a distribution similar to that 

 of Arabis alpina, Sallx herbacea, or Saxifraga aizoides and belongs therefore 

 rather to my European-Alpine- Atlantic group (cf. Vassiljev, 1961 ; D. Love, 

 1960). Also Lycopodium (or Huperzia) selago seems to be a heterogeneous 

 taxon deserving an accurate monograph. 



2. THE CIRCUMPOLAR ARCTIC-SUB-ARCTIC GROUP 



The origin of this group seems to be somewhere in the Arctic during or 

 before the early Pleistocene; during the Ice Ages it attained a broad circum- 



