Morphological classification of ectomycorrhizas ofPinus densiflora

Morphological classification of ectomycorrhizas ofPinus densiflora was conducted. Fifty soil samples containing pine ectomycorrhizas, and 40 pine seedlings were collected randomly in two separate reforested stands ofP. densiflora (45 yr old) from May 1992 to October 1994. Fifty-six types of ectomycorrhizas could be classified based upon microscopically observable morphological characteristics. Fifty percent of the types showed cystidia or other specific characteristics such as laticiferous hyphae in the fungal sheaths, verrucose emanating hyphae and a positive hyphal reaction to UV irradiation. Four mycorrhizal types were confirmed to be formed by the fungiRussula delica, R. mariae, R. nigricans, andCenococcum geophilum, respectively. Although the other 52 types were unidentified mycobionts at species level, it was inferred that they were formed by the fungiHebeloma, Lactarius, Russula andTuber. There was a slight difference in the observed mycorrhizal types between the tree ages. Contribution No. 127, Laboratories of Plant Pathology and Mycology, Institute of Agriculture and Forestry, University of Tsukuba.