CRAPHIS ScnIPTA - Universitetet i Oslo

GRAPHIS SCRIPTA 5 (1ee3)
is therefore interesting to note that S.
omphalarioides on its northernmost localities
(in Nonvay) prefers the less acidic Populus
temula, a phorophyte it also occurs on in its
northernmost Portugese localities. .S.
omphalaioides quite frequently occurs in
orchards, parks, churchyards, along roads (see
Tavares 1954) etc. where the porous bark of
the trees are nutrient-enriched. It appears also
to be dependent on rather high humidity.
,S. omphalarioides is normally a lowland
species occuring from sea-level to a few hundred
meters altitude. Exceptions are from the
southernmost localities in southern Spain,
where it ascends to 1000 m (Degelius 1955),
the Canaries (1300 m) and Cape Verde Is.
(1500 m, Mies 1989), certainly avoiding the
drier, hotter lowlands there.
Phytogeography
S. omphalarioides is basically a Mediterranean
species with a western tenderc!, also reaching
Macaronesia (Figure 2). This is a well-known
pattern, shared by a number of lichens, for
example Pannaia olivacea P. M. JOrg.
(Jorgensen 1978). Such lowland Mediterranean
species rarely reach far north on the
Atlantic coast of Europe, although there are a
few examples of this, e.g. Leptogium coralloideum
(Meyen & Flotow) Vainio (Jorgensen
1993), a species which has its northernmost
locality in Scotland. The highly disjunct,
northern localities of S. omphalarioides near
the Arctic Circle, are anomalous. Species
reaching this far north, normally have much
wider distributions in the atlantic-mediterranean
region and reach much higher altitudes
in the south. Pannaria ignobilb may serve as a
useful comparison, since it has some ecologically
anomalous occurances close to the Arctic
Circle (JOrgensen 1.978). In the Mediterranean
region it reaches 1600 m altitude, and in
Yugoslavia is mostly found in the Fagus
forests at 700-900 m altitude; in contrast there
are no records above 1000 m for S.
omphalarioides in the region, and in
Yugoslavia none above 300 m. P. ignobilis
although not occurring continuosly along the
Physma omphalarioides 15
coasts of Europe, is present both in Great
Britain as well as in southern Nonray.
From these facts it is not unreasonable to
conclude that it would be impossible for ,S.
omphalarioides to grow so far north, and to
challenge the identification of these collections.
The material is, however, quite typical
and in one locality (Tjotta, Offersoya) richly
developed (see Degelius 1955). The type of
habitat is very similar to that found further
south: coarse-barked trees (here Populus)
near a road close to the sea, but the temperatures
are at considerably lower levels, about 10
degrees lower on average. The mean January
temperature of the Nonvegian localities is
about 0 oC, frosts occur several times during
the winter, and the mean July temperature is
about L4 "C.
Obviously S. omphalaioides must have a
wider ecological amplitude than its distribution
in the Mediterranean region indicates. It is
therefore hard to understand why there should
not be any suitable habitats between southern
Portugal and the Arctic Circle. Like Degelius
(1955) we therefore believe that S.
omphalaioides still remains to be discovered
there, but must admit that 40 years have
passed without records of this species, in spite
of high collecting activity. Perhaps this after all
is one of those inexplicable, unlikely cases of a
chance long-distance dispersal which succeeded.
Specimens examined (selected).' Nontay.
Nordland: Alstahaug, Alsten, Skei, 195L,
Degelius (Degel.). Tjotta, Offersoyo, N point,
1951, Degelius (BG, BM, Degel., O, S, UPS).
Nord-Trqndelag: Kolvereid, N of lake Mulstadvann,
1938 & t954, Ahlner (Degel., S);
Namsos, Otteroya, Finnanger, L992, Tpnsberg
(BG). Portugal. Beira Littorah Coimbra, near
town, L93I, Degelius (Degel.); d:o, on western
river bank, 1980, Moberg (UPS). Estemadura:
Almelao (near Setubal), L943, Solerinho
(UPS); between l,ousa and Venda do Pinheiro
near Lisboa, 1955, Tavares (Lich. Lus. Sel.
Exs. 57, BM, O, UPS). Algarve; Rocha de
Pena, Bonafim, L973, Jones (BM); Vale de