Monoblastiaceae Acrocordia gemmata Growth type crustose Chemical results negative. Perithecial wall remains brown in K Widespread on mature, rough-barked trees, especially Ash, Oak and Elm, rare on smooth-barked trees. Thin white or light-grey thallus, large black perithecia (0.5-1mm diam), the ostioles +/- off-centre. Some scattered pycnidia. The spores are colourless, 1(-3) septate, 15-27(-30) x 8-12 µm. Microscope photographs below. Similar: Acrocordia cavata Scarce, smaller perithecia and spores Anisomeridium biforme. Smaller perithecia and spores, perithecial wall green in K

Microscope photographs



Acrocordia gemmata
Studland and Badbury Rings, Dorset. November 2013 and March 2016