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  • Under Assessment
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Boletus loyo Phillippi

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Scientific name
Boletus loyo
Common names
Chilean porcini
porcini of the South
IUCN Specialist Group
Mushroom, Bracket and Puffball
Assessment status
Proposed by
Giuliana Furci
Giuliana Furci
Ricardo Garcia-Sandoval, Roberto Garibay Orijel, Camille Truong
Giuliana Furci
Comments etc.
Tor Erik Brandrud, Anders Dahlberg

Assessment Notes

Butyriboletus loyo


Assessment made directly into IUCNs database SIS in July 2019.

Taxonomic notes

Boletus loyo Phillippi ex. Spegazz. is an ectomycorrhizal species growing on soil, solitary or in small groups, in association with Nothofagus spp. (Palfner 2001). It forms fruiting bodies in late summer to autumn (March to May approx.) that are unmistakable for their size and characteristic colors. The pileus is 60-350 mm wide, dark red, concave to flat, pulviniform, smooth, dry, glutinous when wet. The hymenium is tubular, yellow, turning blue when bruised, with pores up to 1 mm in diameter. The stipe is 80-150 x 40-70 mm, yellow with a reddish base, broadly claviform to bulbous. Spores are fusiform, 11-17 x 4-6 μm, yellowish, smooth, not amyloid (Horak 1977, Garrido 1988).

Why suggested for a Global Red List Assessment?

Boletus loyo is currently endemic to Chile and was reported as endangered (A2c-d) in the red list of Chilean species, according to the Reglamento de Clasificación de Especies Silvestres (RCE). It is a comestible species that is consumed and sold locally, mainly in the regions of Biobío and Araucanía. We propose to include this species in the global red list, considering its restricted distribution range in specific association with Nothofagus spp., a reduction of population size linked to habitat fragmentation, climate change, and potential pressure from its local consumption and marketing. Proposed as Endangered as its EOO has suffered a 70% reduction in the last 20 years.

Geographic range

Boletus loyo occurs in Nothofagus spp. forest of Chile, between the regions VII and X (Maule, Biobío, Araucanía, Los Ríos), from sea level to approx. 1300 m. The species was first described by Spegazzini (1912) from Nahuel Huapi National Park, Neuquén, Argentina. No holotype specimen was mentioned and Singer & Digilio (1957) proposed to consider the type of “Boletus loyus” Espinosa (1915) from Concepción, Biobío, Chile, as the same species. No other mention of Boletus loyo have been made from Argentina since Spegazzini (1912) species description, as Niveiro & Alberto (2013) erroneously mentioned it in Tucumán. Since this large-sized, unmistakable mushroom species of high edible value cannot be easily overlooked, Boletus loyo is therefore probably extinct in Argentina.

Population and Trends

Most historical occurrences (older than 2000) of Boletus loyo come from the southern part of its distribution range, with 7 locations in the Chilean region X (Los Ríos) in addition to Spegazzini (1912) species description from Neuquén, Argentina. On the other hand, only one observation (GBIF) was made in 2016 in the Chilean region X, while most recent occurrences (later than 2000) of Boletus loyo come from the northern part of its distribution range, with 7 locations in the Chilean region VII-IX (Maule, Biobío, Araucanía). Only two historical observations (older than 2000) were made in 2016 in the Chilean region VII and VIII (Maule, Biobío). Today, Boletus loyo is mostly consumed and sold in Biobío and Araucanía. Because of its large-sized, colourful and unmistakable fruiting body of high edible value it is unlikely that its known distribution is due to subsampling.

Extend of occurrence before 2000 = 78,964 km2
Extend of occurrence before 2000 = 23,488 km2
Reduction = >70% of the distribution
Criteria proposed EN A4c/d

Population Trend: Decreasing

Habitat and Ecology

Ectomycorrhizal species fruiting on soil and litter, alone or in small groups, from late summer to fall, in Nothofagus forest, in particular N. obliqua and N. dombeyi (Horak 1977, Garrido 1988, Furci 1988), less frequently N. alpina (Horak 1977) and N. glauca (Donoso 1990, Palfner obs. pers., Sandoval obs. pers.). It is frequently observed in Coihue-Roble forest.

Subantarctic ForestTemperate Forest


Its major threat is over-exploitation for human consumption. This species is an edible mushroom with a high commercial value that is sold fresh locally. The basidiomes are harvested with mycelium attached and are smaller every year. It is possible that the decline in size and number of individuals is caused by over-harvesting. Additionally, this species is associated with a reduced and fragmented Nothofagus forest. Deforestation and forest fires due to drought and climate change are a growing threat.

Human intrusions & disturbanceWork & other activitiesHabitat shifting & alteration

Conservation Actions

Boletus loyo was reported as endangered (A2c-d) in the red list of Chilean species, according to the Reglamento de Clasificación de Especies Silvestres (RCE). Understanding adequate harvest methods for low impact on the mycelium is currently underway.

Research needed

Biology of the species, such as host specificity
Range shift

Life history & ecologyHarvest, use & livelihoodsPopulation trendsHarvest level trends

Use and Trade

Boletus loyo is a comestible species that is consumed and sold locally, mainly in the Chilean regions of Biobío and Araucanía.


Barrera (1984) Catálogo de la colección de hongos de Rolf Singer. Publicación ocasional de Museo Nacional de Historia Natural No. 40. Ediciones Dirección de Bibliotecas, Archivos y Museos, Santiago.

Comité clasificacíon de especies silvestres, 11o Proceso de Clasificación de especies, Ministerio de Medioambiente, Gobierno de Chile.

Donoso (1990) Ecología forestal, el bosque y su medio ambiente. Editorial Universitaria, ISBN 956-110167-9.

Espinosa (1915) Hongo nuevo chileno, el loyo, Boletus loyus Espinosa, n. sp. Boletín del Museo Nacional de Historia Natural, Chile 8: 5-11.

Garrido (1988) Agaricales s.l. und ihre Mykorrizen in den Nothofagus-Wäldern Mittelchiles. Bibliotheca Mycologica 120, J. Cramer, Berlin, Stuttgart, ISBN 3-443-59021-7.

GBIF Secretariat (2019) GBIF Backbone Taxonomy. https://doi.org/10.15468/39omei. Accessed via https://www.gbif.org/species/6016517 on May 23, 2019.

Furci (2013) Hongos de Chile, Andros Impresores, ISBN 978-956-9284-00-7.

Horak (1977) New and rare boletes from Chile. Bol. Soc. Arg. Bot. 18: 97-109.

Mushroom Observer (2019) [https://mushroomobserver.org/320839?q=nRhZ]. Accessed on May 23, 2019.

Mycology Collections Portal (2019) [http://mycoportal.org/portal/collections/list.php]. Accessed on May 23, 2019.

Niveiro & Alberto (2013) Checklist of the Argentine Agaricales 6. Paxillaceae, Gomphidiaceae, Boletaceae, and Russulaceae. Mycotaxon 123: 491.

Palfner (2001) Taxonomische Studien an Ektomykorrhizen aus den Nothofagus - Wäldern Mittelsüdchiles. Bibliotheca Mycologica 190, J. Cramer, Berlin, Stuttgart. ISBN 3-443-59092-6.

Singer & Digilio (1957) Boletaceae Austrosudamericanas. Lilloa 28: 247-268.

Spegazzini (1912) Mycetes argentinenses (Series VI). Anales del Museo Nacional de Historia Natural Buenos Aires. 23:1-146.

Valenzuela (1993) Estudio sistemático, corológico y ecológico de los Agaricales sensu lato de los bosques autóctonos de la Región de Los Lagos en Chile. Tesis de Doctorado, Universidad Alcalá de Henares, España.

Known distribution - countries

Regional Population and Trends

Country Trend Redlisted