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Maritime sands 109Fig. 3. The same area as on Fig. 2after 21 years. Although thesuccession· is rapid it will last along time before the dunes arefully stabilized. The new smalltufts are Oorynephorus canescens,reproduced by · means of seeds.To the right Oarex arenaria withmainly vegetative propagation.Closed pinewood will be the finalstage of the succession. Aug. 18,1958. Photo Bengt Pettersson.The ridges are separated from each other by depressionswhich sometimes could be called duneslacks or even dune marshes. The deflation hasremoved the sand down to the subsoil water level,or the accumulation has dammed up the waterlevel giving rise to fens or marshes.MARITIME SAND HEATHS.-ln most districts,however, the foredune is succeeded inland byrelatively smooth dry sandy fields. From thevicinity of Vitemolla in East Skane SERNANDER(1925a) described a now classical transect acrossthe different belts of a sandy shore illustrating themain types of vegetation. Next to the foreduneSERNANDER found a coastal heath characterizedby Festuca polesica, farther landwards followedby heaths dominated by Oorynephorus canescens.The mobile dunes were referred to the epilittoralby SERNANDER (1917, p. 92) who found them to besituated behind the supralittoral deflation areas.It does not seem to be justifiable to place theseAmmophila dunes in a different belt from that of theFestuca polesica and Oorynephorus canescens heaths,because the latter vegetation often constitutessuccessional stages developed from the A m mop hiladunes. Besides, Ammophila may also immigrateinto the coastal sand heaths dominated by lowgrowinggrasses. It is difficult to parallel the vegetationbelts distinguished on coasts with mobiledunes with belts along other shore types.0. ANDERSSON (1950a) distinguished betweenheaths on rich alkaline soils (Koelerietum andAvenetum) and heaths on rather poor acid soils(Corynephoretum). The two main types of the richergrass heaths, the sand grass heath (Koelerietum)and the meadow-like grass heath (Avenetum) are,according to ANDERSSON (I.e.). conditioned by differentgrain size of the soils, the former containingcoarser fractions of sand. ANDERSSON's "meadowgrass heath", Avenetum, has a very rich contentof species and it is emphasized by ANDERSSON thatthis vegetation is very unstable and will developinto forest when no more exposed to human influence,especially grazing.Also the sand grass heath, Koelerietum, has to begrazed if it shall retain its character. It comprisesthe Festuca polesica heath and is further characterizeda hove all by the occurrence of K oeleriaglauca, a south-eastern species which, however,is frequent along the west coast of Jutland.This type of heath has an element consisting ofseveral continental species and . many southerncalcicolous therophytes characteristic of "alvar"vegetation on Gotland and bland, e.g. Kohlrauschiaprolifera, M edicago minima, Oerastium glutinosum,Hornungia petraea, etc. (c£. ANDERSSON & WALD-Acta Phytogeogr. Suec. 50