Even while this fungus is small, it grows in fascicules with a large number of fruit bodies, so it is not commonly overlooked. The Sierra de las Cruces-Chichinautzin is the surrounding forest of Mexico city and its fungi have been studied extensively for a century. Singer (1974) published the Monograph of Favolaschia including Mexican materias. So the few records of the species are not likely due to under-sampling. Because the only known subpopulation of the species is so threatened by the expansion of Mexico city (one of largest urban areas in the world) it should be protected.
Favolschia roldana should be listed as Vulnerable under the criteria B2ab(ii,iii). This is a species restricted to the high mountain temperate forests (2700-3400 m) surrounding Mexico city. Even counting the whole Sierra de las Cruces-Chichinautzin mountain range, the maximum potential area of occupancy of the species is 1730 km2. In this region there are only two known locations in one subpopulation.
Its habitat has been under a continuing decline due to the expansion of Mexico city, the urbanization of forests and the construction of roads and highways. Global warming will also contribute to a continuous reduction of the quality and extent of this habitat.
Favolaschia roldana has small sessile sporocarps, 1–5 × 1–3 mm in diameter, pinkish brown colored becoming gray to pale brown when dried. It has 1–2 hymenial pores per mm, and ellipsoid, hyaline, smooth basidiospores. One of its more distinguishing characteristics is the presence of numerous claviform acanthocystis on hymenial surface, pileipellis and even in the inner part of the hymenial pores. Favolaschia andina and F. antarctica are close species, which have been reported from south America, growing at similar elevation range around 3000 m. Favolaschia andina has a yellow to brown-greyish color when dried and small basidia compared to F. roldana. Favolaschia antarctica differs from F. roldana by having a well-delimited stipe and shorter basidia. Favolaschia pegleri and F. sachalinensis, which are lookalikes to F. roldana, both lack acanthocystis (Pérez-Ramírez et al., 2014).
NOTE The documentation of this assessment is being revised and edited when finalized when entered to IUCNs Red-List database. The genus Favolaschia is mostly known from tropical and subtropical ecosystems with few species distributed in temperate forests. Favolaschia roldana is only registered from the south of Mexico City, in Abies religiosa with Quercus, Pinus, and Quercus-Pinus forests, at elevations above 2700 m (Pérez-Ramírez et al., 2014). It grows exclusively on dead twigs and fallen branches of Roldana angulifolia an endemic Asteraceae from central Mexico. Favolaschia roldana should be protected because it is dependent of an endemic plant species of central Mexico. The habitat of both species is highly threatened by land use change, deforestation and pollution induced by Mexico city, one of the largest urban areas in the world.
Endemic to central Mexico. Its geographic range is limited to Abies religiosa with Quercus, Pinus and Quercus-Pinus forests, near Mexico City.
There are only two localities in one subpopulation near Mexico City in central Mexico: at Magdalena Contreras (Rancho Viejo, San Nicolás Totolapan), and at Tlalpan free highway to Cuernavaca. Given its small geographic range, the low number of localities and the continuous destruction of its habitat, its populations are considered in decline.
Population Trend: Decreasing
Gregarious. Growing on woody debris of Roldana angulifolia, an endemic and widespread plant shrub from central and southeast Mexico. Its host, Roldana angulifolia, is associated with fir, pine, and oak forests and also reported from cloud forests from 2700 to 3400 m altitude (Calderón de Rzedowski and Rzedowski, 2001).
The two known localities of F. roladana are close to urban sites, particularly in the forests that surround Mexico City, where pollution, illegal timber extraction, and urbanization are major threats.
The localities are within National Parks; however, in these areas the removal of woody debris for timber use is allowed. Such activities should be regulated since Favolaschia roldana depends on gymnosperms twigs to fulfill its life cycle.
The only substrate that has been described to host Favolaschia roldana is Roldana angulifolia, an endemic species of temperate forests in central and southern Mexico. The main research need is an increase in sampling effort, to elucidate if the known distribution of the species is constrained by the absence of records, or if it represents the natural distribution range of the species. It is fundamental to study the substrate where it develops to ensure its ecological relationships.
There are not reports about edibility or use of this species. It will be not surprising that this species will not have any edible importance, considering it small size and weight.
Pérez-Ramírez, L., Cifuentes-Blanco, J., Cappello-García, S., & Villarruel-Ordaz, J. L. (2014). Favolaschia roldana (Agaricales: Mycenaceae), una especie nueva para México. Revista mexicana de biodiversidad, 85(4), 1019-1023.
Calderón-de Rzedowski, G. and J. Rzedowski. 2001. Flora fanerogámica del Valle de México. Instituto de Ecología, A. C./Conabio. México. 1406 p.
Singer, R. (1974). A monograph of Favolaschia. BEIHEFTE ZUR NOVA HEDWIGIA HEFT 50. Cramer.