Friesia X, 4-5

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on the Helgoland coast found only species which could be referred
to group 1 a (with the exception of Corollospora cristata and C. maritima).
In this area the considerable tidal movement could have inhibited
the formation of fruit bodies on the surface of the substrate
by fungi of the group 1 b and 2, or the substrate could have been
too far away from the place of propagation of the group 2 (and 1 b)
fungi (sensu KOHLMEYER 1966).
The species in both groups must be considered as true marine
fungi and t he difference in mode of fructification is for the time
being the only character wh ich can explain the grouping in marine
coast al forms and open sea forms.
An important question is the fate of the large number of spores
produced by fungi in zone 3 and to what extent the marine fungi are
active in this zone. In order to study this aspect wood test blocks
were buried in 1969 in varying depth from water's edge to the base
of dune. After two years an attempt was made to find those blocks,
but only those from the base of the dune were recovered. Test blocks
buried just below the groundwater 'level were healthy. The test blocks
from a depth of 25-40 cm were all brown-black and covered by brown
mycelia which grew out into the sand. The wood blocks were strongly
decayed by soft rot fungi to a depth of about 11j2 mm, waterlogged
and could not float. On Pinus sylvestris were found: Carbosphaerella
lepto sphariouies, Corollospora comaia, C. trijurcata, Lulworthia sp.
and Remispora st ellata. On Fagus sylvatica: Carbosphaerella leptosph
aeriouie s, Fungus im perfectus (Pho ma sp.). On Populus: Corollospora
trifurcata. On Querq'us robur: Corollospora comaia, Fungus
imperfect us (Moniliales) .
It could thus be demonstrated that fungi from group 1 and 2 are
able to infect wood buried in the sand in zone 3. But how the infection
takes place is not known. A similar experiment with blocks placed
on the surface of the sand was prohibited by the intense use of the
beach for bathing during the summer.
DISCUSSION
There are no reports in Danish literature on the fungal flora of
driftwood lying on the beach, and neither has the sand on the open
North Sea coast been investigated for its contents of microfungi.
Ecclogical investigations have not been carried out on the fate of the