Truffle Genus: Gastroboletus

Gastroboletus subalpinus basidiospore scale = 10 µm

Kingdom: Fungi Phylum: Basidiomycota Order: Boletales Family: Boletaceae

Spore Characters

Not distinguishable from Rhizopogon spores except for Gastroboletus species with the attachment nipple angled to the spore axis. In that case, Gastroboletus spores resemble those of the closely related mushroom genera in the family Boletaceae (Boletus, Leccinum, Suillus, etc.).

View photos of Gastroboletus spores

Sporocarp Characters

Shape and Size: Appearing as a misshapen bolete, 3-10 cm broad, with a flat to convex cap and a short, usually stout stem.
Peridium: Dingy white to brown, in some species with yellow or red tones, dry to moist, smooth to felty or scaly-tomentose, some species bruising blue when handled.
Gleba: A layer of very long, often curved or contorted olive to brown tubes on the underside of the cap; tube mouths are often covered or stuffed with cottony or membranous tissues.
Odor: Mild and pleasant to pungent or farinaceous.

View photos of Gastroboletus sporocarps

Name Derivation

Named by German scientist Heinrich Lohwag (1884-1945) (1926) from Greek, gaster- (literally "stomach" but in mycology referring generally to Gasteromycetes, i.e. puffballs) and -boletus (literally "a superior mushroom," referring to the genus Boletus), hence, "a puffball-like Boletus."

Distribution

Most species are restricted to coniferous forests of the Pacific coastal states, but G. turbinatus extends to the Midwest and Mexico. Gastroboletus boedijnii was described from China.
Season: Generally summer through autumn.
Species known from North Temperate Forests: Nine have been described, and several more undescribed species have been collected in Oregon and California.

Keys and Descriptions

Thiers and Trappe (1969) provided a key and descriptions for most species. Thiers (1989) proposed two new Gastroboletus species, segregates two new genera, Gastrosuillus and Gastroleccinum, on the basis of distinctive sterile tissues, and provides a comprehensive key. Some mycologists combine the genus Gastroboletus into the mushroom genus Boletus. Nouhra et al. (2002) provide a key to all known species of Gastroboletus.