Order: Pyrenulales       Family: Monoblastiaceae Species: Anisomeridium biforme Growth type crustose Photos: On Ash. Ballinagree, Co. Cork, SW Ireland. A thin white to greyish thallus with small, +/- immersed black perithecia (0.3-0.5mm) leaving pits when they disintegrate. The smaller pycnidia often extrude a whitish jelly containing conidia. Spores 1-septate, 12-16 x 5-7, the septum 1/2 to 1/3 distance from upper end. Microscope photographs below. Chemical reactions negative. Common on shaded, smooth-barked trees but easily overlooked. Similar: Acrocordia gemmata has larger perithecia, 0.5-1mm

Microscope photographs

Anisomeridium biforme April 2012