Assessment Notes

Justification

Calostoma cinnabarinum is a widely distributed species, reported in the United States from New England to the southern tip of the Appalachian Mountains and west to Texas continuing south through Mexico into Central America and montane Colombia and the Coastal Atlantic Forest in Brazil. It has also been occasionally reported from China and Taiwan, Province of China. It forms ectomycorrhizal relationships with oaks and may also form associations with mosses. It is most often found in humid forests, especially mountainous areas with high annual rainfall. While not common, its is widely distributed and its population is relatively stable. It is assessed as Least Concern.

---

Geographic range

Calostoma cinnabarinum is a widely distributed species. This species has been reported in the United States from New England to the southern tip of the Appalachian Mountains and west to Texas. In the US, it is most common at higher elevations in the Appalachian mountains where oaks can be found, though a few isolated occurrences have been reported along the Gulf of Mexico from Texas to Florida. In Central America, C. cinnabarinum is known from Mexico, Costa Rica, Panama, Honduras, Guatemala, El Salvador and Belize. In Central America virtually all recorded sightings of this species occurred at an over 1,000 m in elevation, in humid cloud forests. In South America, the species has been documented in Colombia and Brazil (not mapped). In Colombia, it has been recorded in the mountains south of Medellin, and in Brazil, in the eastern stretches of the country. C. cinnabarinum has also been documented in Asia, specifically Taiwan, Province of China and mainland China, although Asian occurrences seem to be very rare and data on these occurrences are lacking.

---

Population and Trends

Calostoma cinnabarinum is uncommon throughout its range. Based on recent recorded occurrences of C. cinnabarinum, any declines are focused in Central and South America where increasing temperatures seem to be limiting the species' range to increasingly high elevations or eliminating subpopulations entirely. Although the population may be in decline in parts of its rage, overall the population is likely stable or only declining slightly.

Population Trend: Stable

---

Habitat and Ecology

This species forms ectomycorrhizal relationships with oaks and may also form associations with mosses. This species is most often found in humid forests. Calostoma cinnabarinum is more common in mountainous areas with high annual rainfall. C. cinnabarinum's preference for higher elevations is more pronounced in warmer regions. This is why in Central America, it is found almost exclusively above 1,000 m, but can be found at lower elevations in the northeastern United States.

---

Threats

In tropical regions, Calostoma cinnabarinum is threatened by habitat loss due to development, logging, agriculture and changing climate, i.e. increasing temperatures and reduced rainfall. For example, occurrences of C. cinnabarinum in Mexico are becoming increasingly rare at lower elevations where it was once found (personal observation). Similarly, increased aridity associated with climate change likely also threatens C. cinnabarinum, which thrives in humid forests with substantial annual rainfall. Future declines should be expected throughout the species' Western Hemisphere range as warming temperatures restrict C. cinnabarinum to higher elevations in Central and South America and the Appalachian Mountains of the US.

---

Conservation Actions

Montane forests in Mexico and Central America need to be protected, although many are protected through international and national level conservation efforts. Conservation efforts may include linked enterprises and livelihood alternatives

---

Use and Trade

While historically this species has been consumed by some native peoples in Hidalgo, Mexico, it is far too uncommon to be of major economic importance.

---

Source and Citation

Mueller, G.M. 2025. Calostoma cinnabarinum. The IUCN Red List of Threatened Species 2025: e.T273224632A273244654. Accessed on 20 November 2025.

---

• Country occurrence