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126 NILS MALMER .STROM 1937, pp. 416 ff.). Before Calluna vulgarisagain1 reaches its former abundance there may bean intermediate stage characterized by Arctostaphylosuva-ursi and Genista pilosa. After about 10 yearsthe moss layer is well developed again and hasscattered lichens intermingled. The intensity ofthe burning and of the subsequent grazing highlyinfluences the proportions between the species, butlittle is known about this from Sweden. Cf.,however, 0LSSON 1964, pp. 125 ff.The Calluna- V accinium community is ratheruniform all over its distribution range in SouthSweden which at least comprises Bohuslan, Halland,south-western SmaJand and the ridges in Skane,except the easternmost parts of that province. Thevery humid area in south-eastern Halland deviatesin Arctostaphylos uva-ursi and Genista pilosa beingcommon there. The Oalluna- V accinium type ofvegetation belongs to the Scano-Danish heath series(BocHER 1943). It differs from more southerlyEuropean heath types especially through theoccurrence of the V accinium spp., T.rientalis europaea;Luzula pilosa, Dicranum undulatum andHylocomium splendens. Several oceanic species areabsent, e.g. Erica cinerea, Hypericum pulchrum(very rare in Sweden) and Carex binervis, whichoccur in the closely related heaths in easternScotland (GIMINGHAM 1961, 1964) and westernNorway as well as Cytisus scoparius and Genista spp.which characterize the Dutch-German heath series(BocHER op. cit.). In the central parts of the SouthSwedish Upland there is a gradual transition frothe Calluna- V accinium community to a grasslandvegetation in which Calluna vulgaris is absent oronly grows in small patches. Agrostis tenuis,Anthoxanthum odoratum, Deschampsia flexuosa, .Festuca ovina and Rhytidiadelphus squarrosus areamong the species which increase eastward . inabundance, together with several herbs. Cf. furtherDAMMAN (1957, Table 2) and ERICSON (1963).The soil beneath the Calluna- Vaccinium communityis clearly podsolized and has a mor typehumus layer. The leached layer is mostly darkcoloureddue to humus but discernible through theweathered mineral grains. DAMMAN (1957) andLrNNERMARK (1960, p. 43), however, report thick,grey leached layers from what is said to representold heaths. The B horizon is developed either as aniron or as an iron-humus horizon, and an iron panmay occur. The reaction of the mor layer is notextremely acid, usually between 4.1 and 4.8.1 Cf.LINNERMARK (op. cit) and SJORS (1961a, p. 44).After reforestation the changing soil conditionsresult in higher acidity in the top layer, especiallybeneath coniferous trees.SOUTH-EASTERN CALLUNA VEGETATION.-Ineastern Skane and in the Blekinge archipelago theCalluna dominated vegetation has a differentcharacter (DAMMAN 1957, GIMINGHAM 1961, BERG­LUND 1963 a). Many of the species in the previoustype of heath vegetation are rare or absent, e.g. theVaccinium spp., Arnica montana, Scot·zonera humilisand Trientalis europaea. Instead a number ofspecies belonging to the vegetation of dry grasslandsare met with. Thymus serpyllum, Galium verum,H ieracium pilosella, H. umbellatum, Agrostis tenuis,A nthoxanthum odoratum and F estuca rubra maybe mentioned. The bottom layer is either dominatedby mosses (Pleurozium, Hylocomium) or by Cladoniaspp., esp. rangiferina and silvatica (sens. lat.).DAMMAN ( op. cit.) distinguishes this community asHylocomieto - Callunetum hieracietosum. FurtherBocHER (1943) treats similar types, including aCalluna-Cladonia heath near Uppsala (Du RIETZ1930a, Table _6), within a Callunion balticum that isdistributed around the southern part of the BalticSea. Cf. also Du RIETZ (1921 b, p. 158, 1925 a and d,1932 b).This eastern Calluna community is found onsandy soil or in rocky areas. The soil profile may becharacterized as a podsoloid (LINNERMARK 1961).The reaction of the humus layer is said to be lessacid than in the previous type (DAMMAN 1957, p.388), but the range of pH given by BERGLUND(1963 a, p. 65) hardly confirms this statement. Cf.also Du RrETZ (1932 b, p. 90).CALLUNA-EMPETRUM COMMUNITY.-Especiallyon fixed sandy soils, often near the sea shore, aCalluna-Empetrum community is found, the two1 All figures given electrometrically measured in suspensionsof 1 vol. fresh sample and 2 vol. dest. water ..Acta Phytogeogr. Suec. 50