Members of the Ph. dimorphospora clade have been isolated most commonly as DSE from coniferous tree roots or from decomposing wood (Menkis et al. 2004), although several other ITS sequences and distinct ITS phylotypes present in GenBank have been reported from other substrates (e.g. EU434847 Ph. repens from Populus and JF340261 Phialocephala sp. M49 from Alnus). In this study apothecia assignable to the Ph. dimorphospora clade were collected from deciduous wood (Acer saccharum, Alnus viridis, Betula alleghaniensis, B. cordifolia, B. papyrifera, Fagus grandifolia) that usually was decorticated and in advanced states of decomposition. Phialocephala dimorphospora s.l. causes soft rot and significant weight loss in deciduous wood (Nilsson 1973, Morrell and Zabel 1985, Wang and Zabel 1990, Held 2013) and is implicated in wood staining (Kowalski 1991). Menkis et al. (2004) hypothesized that Ph. dimorphospora may latently infect healthy trees, causing wood staining when the health of the host declines and decomposing wood following host death. Latent infection of living branches also may play a role in natural pruning (Butin and Kowalski 1986, Kowalski and Kehr 1992, Barklund and Kowalski 1996, Kowalski and Zych 2002). Despite members of this clade being among the most commonly field-collected apothecia in this study, only two isolates of the Ph dimorphospora clade were recovered as endophytes from Picea mariana and Pinus strobus needles (all Ph. nodosa), suggesting needle colonization may be infrequent and opportunistic.