Fungalpedia – Note 584, Rommelaarsia
Rommelaarsia Baral & Haelew.
Citation when using this data: Zhang et al. 2025 (in prep.) – Fungalpedia, Ascomycota.
Index Fungorum, Facesoffungi, MycoBank, GenBank, Fig. 1
Classification: Incertae sedis, Helotiales, Leotiomycetidae, Leotiomycetes, Pezizomycotina, Ascomycota, Fungi
Based on phylogenetic analysis of ITS and LSU sequence data, Rommelaarsia was established as Helotiales genus incertae sedis (Leotiomycetes, Ascomycota) by Baral and Haelewaters (2015), with R. flavovirens selected as the type species. The morphology of Rommelaarsia was represented by the single species, R. flavovirens, which exhibits both sexual and asexual morphs. Rommelaarsia has a psilachnum-like sexual morph, characterized by round, non-gelatinous apothecia, a light greenish yellow ectal excipulum, irregular texture, a hyaline medullary excipulum, obliquely biseriate asci with J+ apical ring, and subcylindrical to fusoid or often clavate-cuneate ascospores (Baral and Haelewaters 2015). The asexual morph has pulvinate, sessile sporodochia producing large multiguttulate, holoblastic phragmoconidia (Baral and Haelewaters 2015). The trait of short hairs on the superficially growing apothecium suggests a potential phylogenetic relationship to Hyaloscyphaceae. However, the phylogeny is uncertain due to insufficient evidence (Baral and Haelewaters 2015). Fresh collections are therefore needed to assign this genus to a more appropriate natural fungal group. Rommelaarsia flavovirens has been found on dead stems of Equisetum arvensis with three collections (one collection not studied) in Western Europe, including France and Netherlands (Baral and Haelewaters 2015). This species appears to be limited to Equisetum arvensis (Baral and Haelewaters 2015).
Type species: Rommelaarsia flavovirens Baral, Tanchaud & Romm.
Other accepted species: Species Fungorum – search Rommelaarsia.
Figure 1 – Rommelaarsia flavovirens. (b–f Sexual morph; a, g–i Asexual morph) b Apothecia in fresh state. c Apothecium in median section. d Smooth marginal hairs. e Asci with J+ apical ring. f Ascospores. a, g–i Asexual state. a Conidiomata (sporodochia) on natural substrate. g, h Conidiophores with young, eguttulate conidia. i Mature conidia. Redrawn from Baral and Haelewaters (2015).
References
Entry by
Jing-Yi Zhang, School of Food and Pharmaceutical Engineering, Guizhou Institute of Technology, Guiyang, 550025, People’s Republic of China, Center of Excellence in Fungal Research, Mae Fah Luang University, Chiang Rai, 57100, Thailand, School of Science, Mae Fah Luang University, Chiang Rai, 57100, Thailand, Guizhou Key Laboratory of Agricultural Microbiology, Guizhou Academy of Agricultural Sciences, Guiyang, 550009, People’s Republic of China.
Published online 11 June 2025