Monoblastiaceae Anisomeridium biforme Growth type crustose Chemical reactions negative. Perithecial wall greenish in K (remains brown in Acrocordia) Common but easily overlooked on shaded, smooth-barked trees Small, +/- immersed black perithecia (0.3-0.5mm) on thin, white to greyish thallus. Smaller pycnidia often extrude whitish jelly containing conidia. Spores 1-septate, (9)12-16 x 4.5-6(7) µm, septum 1/2 to 1/3 distance from upper end. Microscope photographs below. Similar: Anisomeridium polypori and Anisomeridium robustum. Also Acrocordia cavata and Acrocordia gemmata.

Microscope photographs



Anisomeridium biforme
Holton Lee and Corfe Mullen, Dorset. November 2012, April 2025