Pleostigma jungermannicola

Hosts: various leafy liverworts, including Plagiochila porelloides and Gymnomitrion obtusum most recently

Confusion exists with Pleosphaeria haploziae Racov. and P. lophoziae Racov., along with other names. A group in need of revision. My observations may not necessarily prove to all belong to a single taxon.

Black perithecia on leaf axils. Material from Greatwood Copse, VC10, May 2021
Asci in water (1000X). Material from Greatwood Copse, VC10, May 2021
Ascospores in water (1000X). Material from Greatwood Copse, VC10, May 2021. Note possible gelatinous perispore surrounding spores here.
Perithecium emerging from between host lobes. Material on the lower, decaying shoots of Gymnomitrion obtusum. Rehydrated herbarium material 5 months old. Merioneth, VC48, Wales. Sept 2021. Note the difference in size between the emerging perithecium and the smaller fruitbodies of Bryochiton microscopicus around it.
Asci at different stages of development of material on Gymnomitrion. Rehydrated herbarium material 5 months old. Merioneth, VC48, Wales. Sept 2021.
Cropped image of mature spores in asci, mounted in water. Rehydrated herbarium material 5 months old. Merioneth, VC48, Wales. Sept 2021.
Spores in asci mounted in water. Rehydrated herbarium material 5 months old. Merioneth, VC48, Wales. Sept 2021.
Ascospores in water. Rehydrated herbarium material 5 months old. Merioneth, VC48, Wales. Sept 2021.
Ascospores in water. Rehydrated herbarium material 5 months old. Merioneth, VC48, Wales. Sept 2021.
Ascospore in water. Rehydrated herbarium material 5 months old. Merioneth, VC48, Wales. Sept 2021.
Hyphae on host cells, seen in water. Rehydrated herbarium material 5 months old. Merioneth, VC48, Wales. Sept 2021.
Some setose ascomata on Anastrophyllum minutum. Scotland, leg. R. Whytock.
Well-developed hairs from the above collection (Anastrophyllum minutum).
Asci and spores of Scottish material on Anastrophyllum minutum. Leg. R. Whytock.