Aerialroot-like galls of Laurobasidium hachijoense formed on a trunk of Cinnamomum japonicum [..] all consisted of deformed plant tissue and the fungus. Basidia and basidiospores are produced on the surface of the gall.

Large clavarioid galls and narrowly cylindrical clamped hyphae characterize the genus Laurobasidium (Jülich 1982) but in the case of L. hachijoense, clamped hyphae were not found as reported by Iijima et al. (1985).

A fungal disease with aerial-root-liked gall symptoms on Cinnamomum subavenium in Khao Yai National Park, Northeastern Thailand is reported, and the causative agent identified as Laurobasidium hachijoense.

Fungal infection has caused galls (flat, subiculum-like structures) forming around small branches of the seedlings, or in clusters of perennial galls forming on stems of the trees (Figure 1). In the early wet season (June–July), the aerial-root-like structures emerge and expand from these galls. The number of such root-like structures per gall varied from a few to hundreds. These root-like structures had a diameter of 5–7 mm. On the medium-sized trees and during the wet season, they could increase their length up to 1 meter. Between the late wet season and the early dry season (August–November), the yellow-green surface of these root-like parts became velvety due to fungal sporulation. They gradually turned brown during the dry season and in the summer time became dried up and fell to the ground.