THE ECOLOGICAL DISTRIBUTION OF MYCORRHIZA OF BEECH

S ummary The following conclusions may be drawn from the determination of mycorrhizal spectra on beech at eight localities in Czechoslovakia. Altogether thirty‐three sub‐subtypes of ectotrophic mycorrhiza on beech were described in Czechoslovakia, of which seven are entirely new, namely: De, Df, Ed, Ee, Ek, Ih and Ik (see Dominik, 1959). Maximum frequencies of ectotrophic mycorrhizas were found down to a depth of 15–30 cm. With increasing depth the number of short roots and mycorrhizas decreased and the mycorrhizal spectrum narrowed. The quantities and types of humus were a decisive factor influencing mycorrhiza formation. Subtype E was the most frequent (20.26%) of all mycorrhizas. The richest mycorrhiza spectrum of four comparable localities was at Albrechtice in the Ore Mountains where fourteen sub‐subtypes of ectotrophic mycorrhiza were found despite a heavy deposition of industrial ash from power plants and a high concentration of SO 2 in the atmosphere. No differences were found in the mycorrhiza variety between beech saplings (5–10 years) and older trees (over 100 years), nor was the occurrence of individual mycorrhiza strains characteristic of beech trees of different age.