38 ^'- H. Ostenfeld. 



ol aritir rfijions, oiily llu' mon* liii,'h-anlir [ilaiils arc lit for sufh con- 

 ditioiis. Willi ifiraril In .Xnrlli-CirtM'nlainI I I hink I hat a good deal 

 (»f tht' jirt'snil iHuth tuast lUu'a lias beeii ablr tn sui\i\t' in ripccnland, 

 althoii^di not its nortlirni parts; but with rogaid lo llic itsl 1 lonsider 

 thoin as liaviiiij iniiiiii^rated from otlicr coiintrios, and I agroe wilh 

 SiMMONs in taking for grantod that th(^ iinniigrants mainly caino from 

 Arctic America, which also thc tahle II makes tho more j)rol)al)le, and 

 ft)r North-GnHMiland il seoms iialiiral to thiiik Ihem cross over tho 

 narrow Smith Sound (ice-covered in winter time) to Infj^lefield Land 

 and j)roceed from there both southwards and northwards. The i in mi- 

 gration must have been favoured by I hat postglacial epoch when the 

 chmate was somewhat warmer than it is at thr present lirne, and several 

 species which now occur only farther south in Greeidand mav at that 

 time have crossed Smith Sound. 



If \ve look on llie list, the species Avliii h nowadays have a circnin- 

 polar distribution do not give many hints as to their way of immigra- 

 tion or to their possible survival in Greenland during the ice-age. 1 should 

 think that most of those which did not siirvive, immigrated fmin west, 

 but I (ind it useless to go into further details in that respect. 



More favourable is the matter with regard to the species whirh 

 have a restricted distribution in the arctic coimtries. 



Some of the species with eastern distribution outside ol Greenhmd 

 (see p, 29) are without doubt rather recent immigrants, namely Draba 

 Adamsii, Taraxacum arcticiun, Arenaria ciliata pseudojrigida and 

 Raniinculiis glacialis^); their area of occurrence in Greenland is rather 

 restricted and they are most probably extending it. Com tining llie 

 forms of JJnjas octopelala it is, as mentioned above (p. 30), very difficult 

 to form a delinite idea of their immigration, bul I Ihink il probable 

 that the same holds good for Ihem. 



Hather uncertain and not inn( h clear is the case with Carex saxa- 

 tilis am! Arrnaria ciliata norvegica; as the latter is often a sea-shore 

 plani in arctic countries, it may have arrived with the currents; but 

 it may also be a very old species with a nnK h wider distribution in 

 former time, what its occurrence fai- IVoin lin' sea in llie Kocky .Moun- 

 tains makes more probable. The sea-currents account, I Ihink. for the 

 riispersal of a few other species, namely Carex glareosa, C. saiina sub- 

 spathacra, Puccinellia phnjganodes and juThaps other species of the 

 same genus, Ilonckrnija jirploidrs, Slclhirid htinn'fusa and Mcrlc/isia 

 maritima, 



The rather numerous sj)ecies (31) with westeiii distribution have 

 undoubtedly arrived from Arctic America. A few^ of them only went 



*) Also Polemonium boreale Adams, in Greenland only frtund on the east coast 

 between 75° and 74° N. Lat. 



