Bactrodesmium abruptum
Anamorph: conidiomata absent. Sporodochia 100-300 (-500) µm diam., scattered, punctiform, shining black. Mycelium immersed, hyphae 1-5 µm diam., pale to mid brown. Conidiophores fasciculate, formed at the ends of hyphae emerging from the substratum surface, to ca 40 µm in length, 2-3 µm diam. at the base, broadening to 3-5 µm diam. at the apex, usually unbranched, flexuous, ± hyaline to pale brown. Conidiogenous cells monoblastic, not clearly distinguished from the conidiophore cells, ± cylindrical. Conidia 32-70 x 12-17 µm, 3-5 µm diam. at the base, solitary, terminal, clavate, the apex rounded and the base truncate, the upper part mid to dark brown, becoming progressively paler towards the base, 3- to 7-septate, the penultimate cell much longer than the others, with dark bands at the septa, the uppermost one greatly thickened and obscured by the melanized wall. Epispore, gelatinous sheath and appendages all absent.
Teleomorph: not known.
Not formally assessed, but the species is widely distributed. It is certainly under-recorded, and would probably be considered as of Least Concern.
Distinguished by the large clavate conidia with transverse septa and spore walls with thick black bands.
On rotten wood of various broadleaved trees, including Acer, Fraxinus, Populus and Quercus.
Scattered throughout the British Isles, with most records from the south and central England. There are a few reports from Yorkshire, N and S Wales and the Western Isles.