Ribosomal gene sequence data were obtained from a nonfruiting culture originally identified as Ceratocystis brunnea R.W. Davidson; this species was considered a nomen dubium by Upadhyay (1981) due to a presumptive lack of teleomorph material. The data showed that C. brunnea is a valid species that should be transferred to Ophiostoma, demonstrating that DNA data can compensate for the presumed or actual lack of morphological features lost during either long-term culturing or disintegration of holotype specimens. Use of partial large ribosomal sequence data to assess the relationship of C. brunnea to other Ophiostoma spp. showed that it is not a synonym of Ophiostoma piliferum (Fr.:Fr.) Syd. & P. Syd. as has been suggested; instead, it appears to be distantly related to Ophiostoma piceae (Munch) Syd. & P. Syd. The data obtained for the Ophiostoma piliferum strains included in this study suggest that hardwood-derived isolates may be distinct from those obtained from conifers. In addition, molecular characters support transferring Ceratocystis pseudonigra Olchow. & Reid, Ceratocystiopsis concentrica (Olchow. & Reid) Upadhyay, Ceratocystiopsis pallidobrunnea (Olchow. & Reid) Upadhyay, and Ceratocystiopsis crenulata (Olchow. & Reid) Upadhyay to Ophiostoma.