MORPHOLOGICAL AND ANATOMICAL CHARACTERIZATION OF BLACK ALDER ALNUS-GLUTINOSA (L.) GAERTN. ECTOMYCORRHIZAS

Ectomycorrhizal types of black alder [Alnus glutinosa (L.) Gaertn.] co llected over a 3-year period within an alder forest were characterised by morphological and anatomical features. Of the total of 16 types, 1 4 are described for the first time in this paper. Eight identified typ es belong to the genera Russula, Lactarius, Naucoria, and Cortinarius, while eight further types remained unidentified. In some cases, simil arities of mantle features indicate relationships to identified mycorr hizas. Mycorrhizas of Naucoria escharoides and N. subconspersa were no t distinguished. Two unidentified mycorrhizal types exhibited hyphal m antle structures very similar to these Naucoria species. Within the ge nus Cortinarius, mycorrhizas of C. cf. helvelloides were easily distin guished from all other Cortinarius-like mycorrhizas described on Alnus , which in general showed little anatomical variation. Two further uni dentified mycorrhizas, ''Alnirhiza lilacina'' and ''A. violacea'', pro bably also belong to Cortinarius. The ectomycorrhiza of Russula pumila was the only identified type within the genus Russula, but the uniden tified type ''Alnirhiza cremicolor'' also likely belongs to this genus . Three Lactarius species were present in the experimental plot. Two s pecies (L. obscuratus and L. omphaliformis) had indistinguishable myco rrhizal types, but were easily differentiated from the mycorrhizas of L. lilacinus, which caused intracellular penetration of Hartig net hyp hae into epidermal and cortical cells. All other mycorrhizal types of black alder exhibited a paraepidermal Hartig net without penetration o f root cells. Two unidentified mycorrhizal types ''Alnirhiza atroverru cosa'' and ''A. cystidiobrunnea'', already described from North Americ an Alnus rubra as unnamed morphotypes, showed no similarity to identif ied mycorrhizas. All 16 mycorrhizal types appeared to be specific or a t least typical for alders, since they have not yet been reported from other tree species.