Ascodichaena rugosa Butin
Polymorphum rugosum (Fr.) D. Hawksw. & Punith Anamorphe
Dichaena faginea (Pers.) Fr. Anamorphe
Dichaena rugosa Fr. Téléomorphe
Opegrapha faginea Pers. Téléomorphe
Bark tree parasite Ascomycete fungus.
Exist under 2 states : perfect state, sexual (Teleomorph) very rare and the imperfect state, asexual (Anamorph) very common.
Anamorph : visible as darkish ellipsoid horizontal strips on smooth bark of trees; these strips are formed by a highly rough to warted tissue, dark-brown, dark, where fungus hyphae and host cork cells are intertwined (due to reaction to infestation), to the edge pycnidia are found as big black dots. Pycnidia are permanently reniewed during each favourable period and are replaced by rough tissue inducing a fungus centrifuge growth. Reproduction of this imperfect state is done through macro and microconidia. Species very common on trees with smooth bark and notably Fagus where it can develop large colonies.
Teleomorph : perfect state with black apothecia, 1-2 mm, ovoid, long and irregular, with a crack or stellate opening (the general aspect of apothecia suggested to classifiy this species as an Opegrapha s.l. easily confused with, notably Graphina pauciloculata). Ascospores number in asci variable, colourless, warted, ovoid to ellipsoid, 18-24 x 13-16 µm. This state is very uncommon and can be observed on Quercus bark already well covered with lichens, particularly Enterographa crassa. N.B. Not to be confused with Stigmidium microspilum that is not warted/rough and has perithecia.
N.B. This species is highly variable, and consequently has a great number of synonyms.*