Bretziella Z.W.deBeer, Marinc., T.A.Duong & M.J.Wingf., 2017

Beer, Z. Wilhelm de, Marincowitz, Seonju, Duong, Tuan A. & Wingfield, Michael J., 2017, Bretziella, a new genus to accommodate the oak wilt fungus, Ceratocystisfagacearum (Microascales, Ascomycota), MycoKeys 27, pp. 1-19 : 4

Bretziella Z.W.deBeer, Marinc., T.A.Duong & M.J.Wingf. gen. nov.

Etymology.

Named after Theodore W. Bretz who first discovered and described the sexual state of the type species of this genus ( Bretz 1951, 1952).

Diagnosis.

The genus is distinguished from all other genera of the Ceratocystidaceae based on the mycelial mats that it forms on infected oak trees. These mats form pressure cushions or pads that push the bark away from the underlying sapwood. This causes cracks in the bark, exposing the mats to fungal-feeding arthropod vectors, primarily nitidulid beetles.

Type species.

Bretziella fagacearum (Bretz) Z.W.deBeer, Marinc., T.A.Duong & M.J.Wingf.

Description.

Ascomatal bases black, globose, with undifferentiated ornamental hyphae, often embedded in mycelial mat. Ascomatal necks elongated, black at base, lighter at apex. Ostiolar hyphae present. Asci dehiscent. Ascospores one-celled, hyaline, ellipsoidal, occasionally curved, embedded in hyaline sheath. Conidiophores arise laterally from vegetative hyphae, occasionally branched. Conidiogenous cells phialidic, cylindrical, pale to dark brown. Conidia unicellular, cylindrical with flattened ends, hyaline, borne in chains of varying length. Aleurioconidia not present.

Ecology and distribution.

The only known species in the genus causes vascular wilt on various oak species in North America.