Bryophyte parasitism has evolved independently in many different major groups of ascomycetes (Stenroos et al., 2010). Many convergent traits have appeared: tiny fruitbodies, setae for protection against desiccation, reduction in asci / spores produced, etc.

References
- Stenroos, S., Laukka, T., Huhtinen, S., Döbbeler, P., Myllys, L., Syrjanen, K., & Hyvonen, J. (2010). Multiple origins of symbioses between ascomycetes and bryophytes suggested by a five-gene phylogeny. Cladistics, 26(3), 281-300.