288 TYGE W. BOCHER 



A number of low-arctic snowbed-species, as well as species from the snow- 

 protected heath vegetation are able to reach farther north, and they turn 

 eastwards through the inland area at Nordre Stromfjord-Arfersiorfikjord to 

 the Disko Bay mainland (Lines 11-19 in Fig. 2). They are absent from the 

 extremely continental interior at the head of Sondre Stromfjord or, if present 

 here, are montane and rare because they are restricted to certain rare types of 

 habitat. In this group we have Phyllodoce coemlea, Harrimanella hypnoides, 

 Sibbaldia procumbens, Salix herbacea ; among dry soil species Juncus trifidus 

 joins this group, and a species Uke Luzula spicata shows a marked decrease 

 in frequency in the continental pocket at the head of Sondre Stromfjord 

 (Bocher, 1963). 



The world ranges of the species which follow the curves in Fig. 2 (left) are 

 either North Atlantic montane species or sylvicolous boreal species. No true 

 Arctic species behaves in this way. There is, however, one type of Arctic 

 distribution which shows some relation to the southern oceanic type. Some 

 few true Arctic species, near their southern limits in middle west Greenland, 

 are found only in the coastal mountains. Being dependent on low temperatures 

 and some humidity they are exclusively montane in the south though 

 only in the coastal mountains where there is enough snow. This applies 

 to Potentilla hyparctica, Erigeron erioceplialus, and Melandrium apetaJum 

 ssp. arcticum. Finally, some medium Arctic species are distributed in a 

 similar way, being confined to the mountains surrounding the driest 

 inland areas. As examples may be mentioned Ranunculus nivalis, Antennaria 

 intermedia, A. glabrata, Draba crassifolia, and Erigeron Immilis. 



A distributional pattern opposite to that of the southern, humidity requiring 

 plants is found in a number of Arctic-Continental species, some southern 

 species which are dependent on high summer temperature, and some which 

 require certain edapliic conditions connected with a dry climate. A map show- 

 ing the western Umits of these species is shown on the left in Fig. 3. On the 

 right in the same figure is given the distribution of the most important mem- 

 ber of the Arctic-Continental species, Care.x supina ssp. spaniocarpa. There is 

 a concentration of species at the head of Sondre Stromfjord. This is mainly 

 the result of the edaphic conditions here. The chmate causes the formation of 

 ultrabasic soils on dry slopes with soil-water evaporation from the surface or 

 along salt lakes formed in bowl-shaped depressions or valleys with no out- 

 flow to the sea. The most important species here may be Braya novae-angliae, 

 B. linearis, Primula stricta, Gentiana detonsa var. groenlandica. Ranunculus 

 pedatifidus (not the Arctic subspecies). Among species extending their 

 ranges to the larger part of the cross-hatched area in Fig. 2 (left) there are, 

 for example, Draba lanceolata, Pedicularis labradorica, Antennaria affinis. 

 Car ex boecheriana, and related forms (see Bocher, 1 963 ; Bocher and Laegaard, 

 1962). 



The southern Boreal plants which in the north are confined to this inland 



