Assessment Notes

Justification

Bulbilla applanata is a lichenicolous fungus known from South America. It was described based on the formation of bulbils (sclerotia-like sterile structures) and neither basidiomata or conidiomata were observed. There are very few records available for this species, but its population size is projected to be above 18,000 individuals and a significant population decline is not expected. Therefore, it is assessed as Least Concern (LC).

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Taxonomic notes

Bulbilla applanata is the only species in the Bulbilla genus, described in 2014 based on molecular data (Diederich et al. 2014).

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Geographic range

So far this species is known from South America, in Ecuador (Provinces of Loja, Tungurahua and Zamora-Chinchipe), Bolivia (Yungas montane forest) and Chile (Los Lagos, Valdivia) (Diederich et al. 2014).

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Population and Trends

Bulbilla applanata has only been documented from a small number of sites (Bolivia: one, Chile: one, Ecuador: four [not all mapped]). However, given its recent description, distribution, large number of hosts and minute and inconspicuous structures (only up to 400µm in diameter), the total number of sites is expected to be much larger. Therefore, following guidelines by Dahlberg and Mueller (2011), total population size is expected to be around 18,000 individuals, applying a large multiplier for unknown sites (x1,000) and assuming one mature individual exists per patch (individual lichens), and at least three patches per site. A significant total population decline is also not expected, given the wide host breadth and relatively large distribution.

Population Trend: Unknown

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Habitat and Ecology

Bulbilla applanata is a lichenicolous species that parasitises thalli or apothecia of Peltigerales lichens (e.g. Lobariella crenulata, Peltigera sp., Pseudocyphellaria faveolata and Sticta sp.). It is known exclusively from bulbils and neither basidiomata nor conidiomata were observed. Diederich et al. (2014) also hypothesise that this may be a strictly lichenicolous species, and possibly a virulent parasite of hosts. It is often found in montane forests, including the Yungas montane forest (alt. 1,550 m) in Bolivia, a primary montane forest (alt.1,945 m) and a cloud forest (alt. 2,400–3,800 m) in Ecuador, but also in a forest dominated by Nothofagus dombeyi (alt. 920–980 m) in Chile. In some cases, parasitised lichens were found growing on Nothofagus sp., Hieronyma asperifolia or were epiphytic (Diederich et al. 2014).

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Threats

No threats have been identified for this species.

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Conservation Actions

No specific conservation actions are needed for this species. Further records and research into the ecology of this species are needed to help establish distribution limits and better determine the population size.

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Source and Citation

Cunha, S.P. & Gonçalves, S.C. 2025. Bulbilla applanata. The IUCN Red List of Threatened Species 2025: e.T265976067A266020213. Accessed on 23 November 2025.

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• Country occurrence