Xerocomellus amylosporus (A.H. Sm.) J.L. Frank & N. Siegel
Fungal Systematics and Evolution 6: 267. 2020.
Common Name: none
Synonyms: Tylopilus amylosporus (A.H. Sm.) A.H. Sm. (invalid); Boletus amylosporus (A.H. Sm.) Wolfe; Gastroboletus xerocomoides Trappe & Thiers
Basionym: Porphyrellus amylosporus A. H. Smith
For description see Frank et al. & Siegel et al.
With various trees in Northwestern California and the Sierra Nevada mountains (gastroid form).
Unknown, but probably edible.
The amyloid spores are unique in this group. Collections of Xerocomellus amylosporus from dry habitats tend to form gastroid sporocarps. This form has been called Gastroboletus xerocomoides, but the ITS sequence of the type of Gastroboletus xerocomoides and X. amylosporus are identical, so X. amylosporus is the correct name for both forms.
Frank, J., Siegel, N., Schwarz, C., Araki, B., & Vellinga, E. (2020). Xerocomellus (Boletaceae) in western North America. Fungal Systematics and Evolution 6: 265-288. (PDF)
Siegel, N., Vellinga, E.C., Schwarz, C., Castellano, M.A. & Ikeda, D. (2019). A Field Guide to the Rare Fungi of California's National Forests. Bookmobile: Minneapolis, MN. 313 p. (PDF)
Smith, A.H. (1965). New and unusual Basidiomycetes with comments on hyphal and spore wall reactions with Melzer's solution. Mycopathol. et Mycol. Appl. 26: 385-402.
(Protologue)
Thiers, H.D. & Trappe, J.M. (1969). Studies in the genus Gastroboletus. Brittonia 21: 244-254.
Wolfe Jr., C.B. (1979). Austroboletus and Tylopilus subgenus Porphyrellus, with Emphasis on North American Taxa. J. Cramer: Vaduz. 148 p.
Wolfe Jr., C.B. (1986). A numerical taxonomic analysis of Tylopilus subgenus Porphyrellus (Boletaceae). Nova Hedwigia 43(3-4): 515-523.