The main characteristic of ectomycorrhizal fungi is that hyphae form a dense and intertwining fungus on the surface of vegetative roots of plants, and forms a Hartig nets in the intercellular space of the cortical tissue of the roots, but the hyphae do not invade the interior of cells and generally form a distinct fruiting body.
Most of the fungal mycorrhizal fungi are fungi of the subclass Basidiomycetes, of which the mycorrhizal species in Boletaceae, Russulaceae, Cantharellaceae, Amanitaceae, Trichosomataceae, Calavariaceae, and Sclerodermataceae and other species are relatively commom. There are only a few species in the subphylum Ascomycota, for example Elaphomycetaceae, Terfeziaceae and Tuberaceae, etc., and there is only one family of the Ecdoganaceae in the Zygomycotina.
Among these fungi, there are some fungi that produce underground fruiting bodies and are sometimes difficult to find on the ground, such as Rhizopogon, Russula, Tuber, and Eapphomyces etc. But most other mycorrhizal fungi can form macroscopic fruiting bodies on the groundsurface, such as Boletus, Amanita, Russula, Thelephora, Suillus, Hebeloma, Lactarius, Scleroderma and Pisolithus etc. In addition, many of the fungi that form ectomycorrhizae are excellent edible fungi. Among the more than 500 kinds of edible fungi known in China, there are 352 kinds of edible fungus that can form mycorrhiza, accounting for 53.6% of the total resources of edible fungi. Therefore, ectomycorrhizal fungi are not only the species of mycorrhizal fungi, but also an important resource in edible fungi.
Among natural flowering plants, arbors and shrubs mainly form ectomycorrhizae, accounting for about 3% of the total number of flowering plants. According to statistics, plants capable of forming ectomycorrhizae include 43 families and 139 genera. These trees mainly distribute in temperate regions. Myrtaceae and Dipterocarpaceae species in the subtropics mainly form ectomycorrhizae. Some arborous plants can also form ectomycorrhizae and endmycorrhizae, such as Populus, Eucalyptus, Casuarina, Abies, and Tilia. The studies in East China, Southwest, and South China revealed that Pinaceae and Fagaceae plants are the major species that form ectomycorrhizae.
Reference: All pictures are obtained from internet.