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68 OLOF RUNEFig. 2. Aconitum septentrionale. Photo 0. Runewater and good nutritional conditions (cf. HoLMEN'spaper) these plants form tall-herb communitiesoften over man's height (in late flowering orfruiting state Aconitum may reach nearly nine feetin height). Here they occur together with plants ofa wide climatic range but dependent on moist andvery rich soils, e.g. Filipendula ulmaria, Stellarianemorum, Paris quadrifolia, grasses like M iliumeffusum and Oalamagrostis purpurea, shrubs likeDaphne mezereum and Ribes spicatum and ferns likeM atteuccia struthiopteris and Dryopteris dilatata.The conifer forest belt also harbours a gooddeal of mountain plants growing on the shores oflakes and streams as well as in springs and rich £ens.Mountain-centered plants frequent in the coniferbelt are Salix myrsinites, Juncus triglumis, Saxifragaaizoides, Thalictrum alpinum, Bartsia alpina,Astragalus alpinus, Pedicularis lapponica, Saussureaalpina, Gnaphalium norvegicum. With theexception of Pedicularis lapponica and probablyGnaphalium norvegicum they are favoured by lime.Near springs occur Saxifraga stellaris, EpilobiumHornemanni, E. lactiflorum, E. alsinifolium etc.Acta Phytogeog1·. Succ. 50Although usually less frequent there, most of theseplants descend even far into the forests east of themountain area, notably in the calcareous forelandof Jamtland.The appearance of the pre-alpine forest variesdue to edaphic conditions. On slopes with fertilesoils the spruce forast generally grows comparativelydense and tall with an undergrowth of tallherbs, ferns and grasses. On drier, silicious soilsthe acidity and slow decomposition of the littercause a deficient nutrition, and the conifer forestchanges into open stands of slowly growing lowtrees, with the field layer dominated by ericaceousdwarf shrubs such as Vaccinium myrtillus, V.vitis-idaea, Empetrum hermaphroditum, etc.Very steep slopes or cliffs with a more or lesssouthern exposure, so-called south-bluffs, oftenharbour isolated occurrences of southern plants.Thus, Ulmus glabra ssp. montana occurs in isolatedlocalities in the eastern parts of the mountain areain southern Lappland (see also JIM LuNDQVIST inthis volume).In the conifer forests of the mountains the birchis an important element. Most birches are intermediatebetween Betula pubescens and its ssp.tortuosa. Pure ssp. tortuosa hardly occurs in this belt.The other birch species of the lowland and lowerupland, Betula verrucosa var. lapponica, does notascend into the mountain region.In southern Lappland the spruce is the dominanttree of the pre-alpine conifer belt. Pine occursoccasionally in the lower parts of the belt, but inlarge areas seems totally absent from the upperparts. In northern Lappland the proportion of pineincreases considerably. The conifer belt outside ofthe mountains has here both species, but to thewest, as previously stated, a bel.t with only pinemay occur (the regio subsylvatica of W .AHLENBERG).(A similar pine area almost without spruce alsoexists in large parts of the southern Scandes, but inthe Swedish mountains it only reaches south-westernHarjedalen and northernmost Dalarna.) The causesof the shifting proportions between spruce and pinein the conifer belt of the mountains have beenmuch discussed. The absence of spruce in the upperpart of the belt in northern Lappland is, accordingto ENQUIST (1933), due to temperature, according