:Xylariaceae: Biscogniauxia

CULTURES AND ANAMORPHS

One characteristic of undoubted Biscogniauxia species is the general behavior on SME medium (Kenerley and Rogers, 1976) and on 2% oatmeal agar (OMA). On the former medium growth is rapid, a 9 cm diam Petri plate being covered in 7-10 days. The turf is white and thin except for grayish areas where the anamorph is forming. Advancing margins are more or less ropy. On OMA growth is somewhat less rapid. Colonies are usually lanose with gray colors. The reverse of numerous taxa is at first deep green, darkening to black; the reverse of some others is uncolored. Colonies of fungi that behave on both media substantially differently than summarized here are suspected to be of different genera. Color codes in culture descriptions follow Rayner (1970).

Anamorphs in culture are a variation of Nodulisporium Preuss, usually considered to be Periconiella-like (Callan and Rogers, 1986; Jong and Rogers, 1972; Ju and Rogers, 1996). Conidiophores are coarse, usually becoming warty and brown at maturity. Conidia are produced holoblastically from conidiogenous areas that become swollen from repeated conidial production in a limited area. Conidiogenous cell proliferation is essentially sympodial. Branching is from a main axis with apparent "apical dominance." This type of conidial apparatus is found in some Hypoxylon species and is illustrated by Ju and Rogers (1996). Conidia are mostly ovoid to obovoid with a flattened secession scar. They are dry and easily disseminated by wind. In nature, conidia are mostly observed borne between layers of immature stromata, filtering out of ruptures or blowing off of areas where the overlying bark has sloughed. It is known that the conidial states are produced from invaded substrates at times of year when stromata are not being produced, but the extent has not been assessed. Conidia of many, if not all, Biscogniauxia species germinate (see Callan and Rogers, 1986). They are undoubtedly, along with ascospores, effective inoculum.