• Proposed
  • 2Under Assessment
  • 3Preliminary Assessed
  • 4Assessed
  • 5Published

Trappea phillipsii (Harkn.) Castellano

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Scientific name
Trappea phillipsii
(Harkn.) Castellano
Common names
IUCN Specialist Group
Mushroom, Bracket and Puffball
Assessment status
Proposed by
Noah Siegel
Comments etc.
Noah Siegel

Assessment Notes

Taxonomic notes

Described from a collection made in Placer County, California, USA in 1899 (Harkness) as Hysterangium phillipsii, later transferred to the genus Trappea (Castellano 1990). Based on molecular data, it appears to belong in a distinct genus, (Castellano, personal communication).

Why suggested for a Global Red List Assessment?

Trappea phillipsii is widespread in western North America, but rare across the range. It is currently known from twelve sites in California and eleven sites outside the state in the southern Cascades in Oregon, and across the sky islands in Nevada, Utah and western Colorado.
A hypogeous fungus, it is recognized by a rubbery texture, round or irregularly-shaped fruitbody with a thick basal rhizomorph; a white peridium that stains bright pink to pinkish brown, green gleba with a sterile whitish band around the exterior, and presence of a translucent columella help distinguish it in the field. Microscopically, it has small, smooth, oblong spores measuring 3–6 x 1–2 (2.5) μm.

Geographic range

Widespread across California; Known from 12 sites in the southern mountains north through the Sierra Nevada and Coast Ranges, two sites in the southern Oregon Cascades. Also known from nine sites in the ‘sky islands’ of Nevada, Utah and western Colorado.

Population and Trends

This species occurs in a wide range of different habitats found across much of the forested portions of California; but is rarely collected. Only three collections have been made in the past twenty years. Too little is know about this species to assess trends.

Population Trend: Uncertain

Habitat and Ecology

Hypogeous, solitary or scattered under duff and in soil; usually around decaying wood. Found mostly in dryer woodlands with Douglas-fir, (Pseudotsuga menziesii), pines (Pinus spp.), White Fir (Abies concolor), Red Fir (Abies magnifica), and oak (Quercus spp.). Fruiting from spring to fall in the mountains, and during winter and spring on the coast and in the foothills. Spores of this species are presumably small-mammal dispersed.


Very little is known about this species’ preferred habitats,  and dispersed methods (ie. which specific mammal species is involved), making it functionally impossible to meaningfully identify possible threats.

Conservation Actions

Research needed

A greater understanding of the fruiting frequency and dispersal mode (presumably small-mammal dispersed) and the specific mammal species involved would be helpful.

Also identifying if it is a habitat generalist, or requires a specific niche.

Use and Trade

None known.


Castellano, M. 1990. The new genus Trappea (Basidiomycotina, Hysterangiaceae), a segregate from Hysterangium. Mycotaxon 38: 1–9.

Harkness, H.W. 1899. Californian Hypogaeous Fungi. Proceedings of the California Academy of Sciences 1: 241–291

MyCoPortal. Mycology Collections Portal. Available at: http://mycoportal.org

Country occurrence

Regional Population and Trends

Country Trend Redlisted