FungiHighest rank in taxonomy. Groups all life into domains: Animalia, Plantae, Fungi, etc.IUCN NEInternational Union for Conservation of Nature — the world authority on species extinction risk, using standardized criteria. — Not Evaluated — not yet assessed against the IUCN Red List criteria.In ProgressCurrent stage of this record in the editorial review workflow. Recent Sighting
Mycena citricolor
American Leaf Spot
(Berk. & M.A. Curtis) Sacc., 1887
Detailed Texts Multi-lang
Mycena citricolor is a tiny but devastating phytopathogenic fungus, famous for causing necrotic circular spots on coffee leaves. The fruiting body is a small, bright lemon-yellow mushroom (basidiocarp), with a cap barely 1-2 mm in diameter held by a filiform stalk. However, its most common structure in the field are gemmae: small yellow propagules that look like pinheads on the leaf spot. The characteristic symptom is a straw-colored circular lesion with a dark border reminiscent of a bird's eye. This fungus has the unique ability to produce faint bioluminescence under total darkness. It is an obligate parasite that drastically reduces the host's photosynthetic capacity and can cause severe defoliation.
Added by
Anonymous Curator
Reviewed by
Under Review
Last modified by
Julia Trouin
TaxonomyBiological classification ranks placing this species within the tree of life, from Kingdom down to Genus.
PhylumRank below Kingdom. Groups organisms sharing a fundamental body plan (e.g., Chordata = vertebrates and some invertebrates).Basidiomycota
ClassRank below Phylum. Subdivides by structural traits (e.g., Mammalia, Aves, Reptilia, Insecta).Agaricomycetes
OrderRank below Class. Groups related families sharing common ancestry (e.g., Carnivora, Primates).Agaricales
FamilyRank below Order. Groups closely related genera (e.g., Felidae = cats, Canidae = dogs).Mycenaceae
GenusRank just above Species. The first word in the two-part binomial scientific name.Mycena
Taxonomic AuthorityThe scientist who first formally described and published this species, followed by the year of publication.(Berk. & M.A. Curtis) Sacc., 1887
Record Completeness
93%Coming soon
Ecology & StatusHow this species lives: habitat preferences, diet, behavior, population status, and role in its ecosystem.
OriginWhether the species is native (evolved here), endemic (found only here), or introduced by human activity.
Native
Population TrendDirection of change in population size over time: increasing, stable, decreasing, or unknown.
Stable
Trophic RolePosition in the food chain: producer, herbivore, carnivore, omnivore, decomposer, or parasite.
--
EdibilityWhether this mushroom is edible, toxic, hallucinogenic, or of unknown safety. Never eat based solely on this data.
--
Cap ShapeShape of the mushroom cap (pileus): convex, flat, umbonate, funnel-shaped, bell-shaped, etc.
--
Hymenium TypeThe spore-bearing surface of a fungus: gills, pores, teeth, ridges, smooth, or wrinkled.
--
Fruiting SeasonTime of year when this species typically reproduces or flowers.
Wet Season
Recent SightingsWhether this species has been observed in the wild in Costa Rica within recent years.
Yes
Habitat SummaryOverview of the specific ecosystems and environments where this species is found in Costa Rica. Multi-lang
It is distributed across Latin American coffee-growing regions, from Mexico to Brazil. It thrives at altitudes between 600 and 1,600 meters, where relative humidity is above 80% and temperatures are moderate (18-24°C). It prefers coffee plantations with excessive shade and poor ventilation, where rainwater or dew remains on the leaves for a long time. In Costa Rica, it is a persistent pathogen in humid mountainous areas like Los Santos, the Central Valley, and Turrialba.SubstrateThe organic material or host organism this fungus colonizes and decomposes. Multi-lang
Information not available in English. Help us expand this record!BehaviourDaily activity patterns, movement, territory use, foraging style, and seasonal behavioral changes. Multi-lang
It behaves as a facultative parasite that weakens the host. Its life cycle is closely linked to coffee phenology and rain patterns. By causing premature leaf drop, it reduces bean production and can kill entire branches in severe infestations. It affects not only coffee but over 500 host plant species, including weeds and shade trees.Physical Measures
Length (cm)
0.1 - 0.5 cm
Hymenium StructuresMacro photographs of the spore-bearing surfaces used for mushroom identification.
No hymenium surface images available.
Evolutionary AdaptationsInherited traits and behaviors that improve the species' survival and reproduction in its specific environment. Multi-lang
Rain-Dispersed Gemmae: Unlike other Mycena fungi that use only spores, M. citricolor produces heavy, nutrient-rich gemmae (asexual propagules) that detach with raindrop impact. This ensures the pathogen spreads from leaf to leaf within the same shrub or to neighboring shrubs during storms.
Oxalic Acid Production: The fungus secretes oxalic acid to degrade the coffee plant's cell walls and facilitate leaf tissue colonization, creating the characteristic circular necrotic spots.
Main ThreatsDocumented pressures reducing the population: habitat loss, hunting, disease, climate change, and invasive species. Multi-lang
Phytosanitary control and climate change: Intensive use of copper-based fungicides and reduced ambient humidity due to rising global temperatures can limit its incidence, though it remains a major threat in high-altitude zones.
Interesting FactsSurprising or notable facts that highlight what makes this species unique or ecologically important. Multi-lang
Bioluminescence in the Coffee Grove: It is one of the few pathogenic fungi that glows in the dark. Both the mycelium inside the leaf and the small yellow mushrooms emit a very faint greenish light, visible only under absolute darkness.