Russulaceous ectomycorrhizae of Abies lasiocarpa and Picea engelmannii

During a 3-year study of the ectomycorrhizal fungi of subalpine forests in the Front Ranges of the Canadian Rockies, species of Russula and Lactarius were conspicuous mycobionts of both erect and krummholz forms of Abies lasiocarpa (Hook.) Nutt. and Picea engelmannii Parry. Morphological identifications of Russulaceous mycorrhizae were confirmed by comparing polymerase chain reaction amplified ribosomal DNA (internal transcribed spacer region) with that of sporocarp tissue. Restriction fragment length polymorphism analysis using AluI, HhaI, HinfI, and RsaI gave a distinctive profile for each of 14 Russulaceous sporocarps and facilitated the identification of five mycorrhizae. Mantles formed by Lactarii (Lactarius alnicola, Lactarins caespitosus, and Lactarius deliciosus var. areolatus) exhibit characteristic laticifers and pigments comparable to the associated sporocarp. Those formed by species of Russula (R. brevipes and R. silvicola) bear distinctive cystidia or sulphovanillin-reactive cells. Key words: ITS, Lactarius, RFLP, Russula, subalpine, tree line.