Coryneum umbonatum  

Anamorph: conidiomata acervuli, 1-3 mm diam., abundant, subperidermal, scattered, separate, rarely confluent, rupturing the periderm, punctiform to disciform or effuse, rarely pulvinate, dark brown, composed of thin-walled vertically-arranged ± hyaline pseudoparenchyma, becoming more irregular and thicker-walled towards the base. Conidiophores formed from the upper cells of the acervuli, 20-140 X 3-6 µm, cylindrical, branched at the base, erect or flexuous, hyaline to pale brown, paler towards the apices, septate, merging indistinguishably into the vertically-arranged pseudoparenchyma. Conidiogenous cells holoblastic, annellidic, integrated, hyaline to pale brown, cylindrical with usually a single annellation. Conidia (40) 57-72 (-90) X (12-) 13-16 (-18) µm, formed singly from the apex of each conidiogenous cell and subsequent proliferations, narrowly fusiform, only rarely clavate, straight or gently curved, tapered gradually towards the obtuse apex which has a hyaline tip, also tapered gradually towards the truncate base which often carries away part of the conidiogenous cell at secession, medium brown, smooth, 5- to 7-distoseptate, many septa dark brown and prominent, cell lumina considerably reduced and enclosed occasionally in a secondary dark brown layer, apical cell usually darker than the rest, without a gelatinous sheath or appendages.
Teleomorph: appearing on the surface as conic to flattened pustulate ruptures of the periderm 1-2 mm diam., with a central angular black carbonaceous disc 0.5-1.5 mm diam. which eventually crumbles away and leaves an irregular perforation. Ostioles irregularly papillate, but usually not visible. Ectostroma brown-black, truncate-conic, fused with the entostroma. Ascomata perithecia, 300-500 µm diam., clustered in the entostroma with a rich proliferation of brown-black fungous parenchyma at maturity and often outlined by a blackened ventral zone. Interascal tissue of thin-walled paraphyses, sometimes evanescent at maturity. Asci 100-180 x 17-25 µm, clavate,  evanescent at the base, with a thickened apical wall and a small refractive iodine-negative ring, 8-spored. Ascospores usually biseriately arranged, 42-55 (-67) X 6-11 µm, ellipsoidal to cylindric-ellipsoidal, usually 6-7 distoseptate, pale grey-brown at first and eventually becoming dark chestnut brown, the end cells darker and the septa eventually becoming strongly pigmented, the cell lumina globose to ellipsoidal, smooth, without a perispore, gelatinous sheath or appendages.