Leucogaster rubescens
Ann. Missouri Bot. Gard. 11: 395. 1924.
Common Name: none
Fruiting body hypogeous to erumpent, subglobose to pulvinate occasionally with shallow depressions; surface sticky when moist, otherwise dry, uneven, wrinkled or with flat warts, scattered coarse rhizomorphs at the base; peridium thin, <1 mm thick, at first yellowish, becoming flushed rusty orange over a pallid ground color, drying rigid and brittle, KOH negative on surface; gleba firm, composed of whitish, irregularly shaped locules 0.5-1.5 mm broad, exuding a whitish latex when fresh; odor indistinct; taste mild.
Spores globose to subglobose, spiny-reticulate, surrounded by a conspicuous hyaline sheath, 11.5-15.5 microns in diameter including ornamentation; inamyloid.
Solitary or in small groups buried in duff of coastal and montane conifers; fruiting fall to mid-winter; occasional to locally common.
Edible.
Leucogaster rubescens is a basidiomycete “truffle”, nondescript when young, but distinctive in age. Fresh young specimens are pale yellowish, developing a characteristic rusty reddish blush at maturity, at which time the peridium becomes hard and brittle. Other distinguishing features include a firm, white gleba composed of relatively large (1 mm and larger) locules that exude a sticky white latex when fresh, and coarsely spinose-reticulate spores enclosed in a hyaline sheath. Closely related Leucogaster citrinus, yellowish even in age, differs with smaller globose spores, 7.5-11 microns. Pachyphloeus carneus, an ascomycete “truffle,” is similar with an orangish peridium but the peridium is conspicuously warted, not rigid, the gleba is marbled, not loculate, and does not exude a milky latex when cut.
Albee-Scott, S. (2007). The phylogenetic placement of the Leucogastrales, including Mycolevis siccigleba (Cribbeaceae), in the Albatrellaceae using morphological and molecular data. Mycol. Res. 111(6): 653-662.
Fogel, Robert (1975). The Genus Leucogaster (Basidiomycetes - Leucogastraceae). Ph.D. Dissertation. Oregon State University: Corvallis, OR. 114 p.
Trappe, J.M., Molina, R., Luoma, D.L., Cázares, E., Pilz, D., Smith, J., Castellano, M.A., Miller, S.L. & Trappe, M.J. (2009). Diversity, Ecology, and Conservation of Truffle Fungi in Forests of the Pacific Northwest. U. S. Department of Agriculture, Forest Service, Pacific Northwest Research Station: Portland, OR. 194 p. (PDF)
Zeller, S.M. & Dodge, C.W. (1924). Leucogaster and Leucophlebs in North America. Ann. Missouri Bot. Gard. 11: 389-410.
(Protologue)
