Rit (Vísindafélag Íslendinga) - 01.06.1975, Page 135

final vegetation form. Kalela describes Alluvialwiesen in the fol-
lowing terms: “Feldschickt 20-200 cm hoch, völlig oder fast völhg
geschlossen, sie umfasst entweder nur eine einzige Teilschickt mit
einer dominante oder unter dieser Schickt eine schwach entwickelte
untere Teilschickt von kleinwiichsigen oder submersen Arten vor-
handen. . . . In Feldschickt fehlen Zwergstraucher immer and
Weidenstráucher fast stets. . . . Die meisten Arten Laubmoosen
sind deutlich feuchtigkeithebend,” (l.c. pp. 302-303). As we can
see this comes sinprisingly close to a description of the Icelandic
flæðimýri. The Finnish flæðimýri, however, seems to be somewhat
moister than its Icelandic counterpart. Kalela (l.c. pp. 304-311)
describes four types of Alluvialwiesen: “Equisetum arvense Wiese
auf reinem Sandboden und werden in Friihhng stark úbersch-
wemmt.” Calamagrostis neglecta Wiese in sandy, damp soil, de-
void of humus. Equisetiun fluviatile Wiese in coastal areas corres-
ponds perfectly to the E. fluviatile pools here, both in topography
and composition of species. The two former vegetation types com-
pletely correspond to the pioneer sociations of the flæðimýri which
will be discussed at a later stage. Finally there is the Carex aquatihs
Wiese which mostly corresponds to the C. Lyngbyei flæðimýri
although the species are different. Of other Alluvial Wiesen des-
cribed by Kalela only the following are related to Icelandic plant
communities: Ranunculus reptans soz, Alopecurus aequahs f. natans
soz, and Subularia aquatica soz. All those belong to aquatic vege-
tation which has been described by many authors. The flæðimýri
is the most homogeneous formation occurring in Icelandic mires.
All of it belongs to the same association, Caricétum Lyngbyei, where
the character species is the same everywhere and predominates in
vegetation. I have here distinguished three sociations of the flæði-
mýri, all of which are closely related.
78. Carex Lyngbyei sociation
(Tab. XVII A-B 1-7 and Tab. XVIIx A-B 1-9)
The best survey of this sociation may be gained from a descrip-
tion of the vegetation in Hvanneyrarfit in Borgarfjörður which is
vepresented by the analyses in Tab. XVIIx. The flæðimýri is prac-
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