Hypoxylon punctulatum (B. and R) Cke. is one of the common fungi found on oak trees killed by oak wilt in West Virginia. The black effused perithecial stromata are formed within the bark and the outer bark covering is broken off forcibly by means of a ridge of specialized gelatinous tissue which swells and exerts pressure at the edge of the stroma. The thin ectostroma and the gelatinous ridge are thrown off with the bark covering. A conidial fungus belonging to the genus Basidiobotrys is often found in stromatic areas before, and sometimes after, the perithecial stromata appear. The conidial heads are borne on compact fungus pillars, which, by their pressure, form cave-like cracks in the bark. Pure cultures producing the Basidiobotrys conidial stage were obtained from germinating ascospores of H. punctulatum, from bits of immature stromata, and from wood beneath the stromata and conidial fructifications. It is concluded that the conidial stage of Hypoxylon punctulatum, unlike most other spp. of Hypoxylon, belongs to the genus Basidiobotrys.