fulltext - DiVA

156 NILS M.ALMERFig. 5. Narrow "lagg" withpoor fen vegetation dominatedby Oarex lasiocarpaand with a few small shrubsof Alnus glutinosa. (Seefurther MALMER 1962a, pp.284-285.) Left, the mineralsoil with Alnus and Pinussilvestris. Right, the marginalpart of a bog withPinus. The Akhult mire inCentral SmiUand. July 1955.Photo N. Malmer.tris, Tofieldia calyculata (only on Gotland), Pinguiculavulgaris, Primula farinosa, Linum catharticum,Potentilla erecta, Succisa pratensis, Briza media andSchoenus nigricans (only Skane and Gotland).This easily distinguished type of mire vegetation,which has a greater variety of species in slopingsites, belongs to the extremely rich fen vegetation(Eu-Scorpidion) according to Du RIETZ. Thoughsome northern species do occur in it, (in Vastergotland,Ostergotland or both Bartsia alpina, Polygonumviviparum and Leiocolea rutheana and onGotland Bartsia alpina and Pinguicula alpina), thegeneral eharacter of the vegetation is southern. Itis very similar to Schoenetum nigricantis (KocH1926) or Primulo-Schoenetum (OBERDORFER 1957)described by several authors from Central Europe.Cf. BENGT PETTERssoN 1958, pp. 222. ff. and GoRs1964.In sloping fen areas with oozing water or springs,in the districts with calcareous soils in Skane, thereoccurs a different type of extremely rich fen vegetation,resembling Juncetum subnodulosi (KocH1926). Calliergonella cuspidata, Cratoneurum commutatum,Drepanocladus revolvens (intermedius),M nium Seligeri, Philonotis ca.lcarea and Pellia fabbronianaare typical mosses. In the high-grownfield layer Juncus subnodulosus or J. inflexus oftenpredominate. Caltha palustris, Crepis paludosa, Epilobiurnparviflorum, Eupatorium cannabinum, Galiumuliginosum, Hypericum tetrapterum, Menthaaquatica, Valeriana dioeca, Agrostis stolonifera andEquisetum palustre are among the common plants.This community in its typical form is in Swedenhardly found outside Skane, although the twoJ uncus species occur on Gotland as well. Some ofthe mentioned species have their Swedish distributionmore or less confined to Skane (e.g. Hypericumtetrapterum). In Vastergotland and Ostergotland,Cratoneurum vegetation is now rare, and many ofits occurrences have been destroyed there as wellas in Skane, where it is, or was, quite widespread.On the other hand, the Schoenus vegetation seemsto be more widespread outside Skane, and (wheretopography permits) developed on sloping sites aswell.A feeble peat formation and a great supply ofwater rich in Ca are common features of all siteswith · extremely rich fen vegetation. The pH inopen water is near 7.0 or often still higher. The highconcentration of Ca (cf., e.g., WITTING 1947, 1948;Du RIETZ 1950a) may lead to precipitation ofCa003, either as temporary thin deposits or as calcareousfen marl or spring tufa. According to unpublishedinvestigations in Skane by S. WALDHEIMActa Phytogeog1·. Suec. 50