Friesia X, 4-5

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species, and its mycelium can - independent of the host plant ­
survive in the soil for many years (MIKOLA 1948a). With regard to
the carbon nutrition the fungus represents an intermediary form between
a typical mycorrhiza-forming fungus and asaprophyte (cf.
MIKOLA 1948a). Whether Cenococcum acts as a mycorrhiza-forming
fungus or as a saprophyte in arable soil and which role it plays there
can only be c1arified through further examinations.
According to TRAPPE (1964) C. geophilum occurs under both
aretic and temperate elimate conditions and in various plant communities
as forests, bogs, heaths and alpine pastures. Its ability to
grow under different ecological conditions and its occurrence in many
countries with growing conditions which are to a certain extent
similar to the Danish, renders it probable that in a number of countries
C. geophilum is commonly occuring in arable soil.
ACKNOWLEDGEMENT
The author is greatly indebted to Leetor J. KOCH, Department of Plant
Pathology, The Royal Veterinary and Agricultural University (RV.A.U.),
Copenhagen, for the information that Oeno coccum g eophilum was not wellknown
as occurring in arable soil, which was the inspiration for beginning
the present work.
Sincere thanks to Hortonom MAJA FROM for her valuable assistance in
the analysis work and to the staff at the Danish State Seed Testing Station
for extensive help during the work on the present paper.
The warmest thanks are due to Le etor K. H ANSEN, Botanical Institute,
RV.A.U., for assistance at the ch emical examinations of soil samples, and
to Professor N . F ABRITIUS BUCHWALD, formerly he ad of the Department of
Plant Pathology, RV.A.U., for important suggestions and inspiring discussions
during preparation of the manuscript.
The Danish State Research Foundation has supported the collection
of soil samples through a grant to Professor, Dr. phil. VALD. M. MIKKELSEN,
Botanical Institute, RV.A.U.
LITERATURE
Bjorkman, E., 1937: Om inverkan av ammoniumnitrat på g r anmyk or rhizans
utbildning i råhumusmark. - Medd. Statens Skogsforsoksanstalt
30: 631-638.
1949: The ecological significance of the ectotrophic mycorrhizal
association in forest trees. - Svensk Bot. T . 43: 223-262.