Definition of "shiro"

Another commonly used Japanese term in matsutake literature is "shiro". As a Japanese noun, it means castle or domain (fruiting place) of a mushroom. As an adjective, it means white. More specifically, a shiro is the dense mat of fungal filaments ("hyphae" or collectively "mycelium") that matsutake species form in the soil.

1997, David Hosford, David Pilz, Randy Molina, Michael Amaranthus, Ecology and Management of the Commercially Harvested American Matsutake Mushroom‎, page 2

‘Shiro’ refers to the dense mat of fungal filaments that Tricholoma Matsutake forms in soil in association with pine roots and soil particles. It is considered that the amount of mycelia in T. matsutake shiros is closely related to the amount of emerged T. matsutake fruiting body.

2007 September 24, Lu-Min Vaario, “Can we regulate the growth of shiro?”, in Matsutake Workshop‎, archived from the original on 9 June 2022