Truffle Genus: Richoniella

Richoniella asterosporus basidiospores scale = 10 um

Kingdom: Fungi Phylum: Basidiomycota Order: Agaricales Family: Entolomataceae

Spore Characters

Surface: Smooth.
Shape and Size: Quadrangular to angular-knobby, 8-13 x 7-11 µm; not necessarily longitudinally symmetric because of irregular placement of angles and knobs, but attachment straight with spore axis rather than offset.
Wall: Single, thin.
Color in Water: Nearly hyaline to pale pink.
Melzer's Reaction: Not distinctive.
Comments: No other genus of truffle-like fungi has angular-knobby spores. This shape plus the pink to rosy tint of the spores show a close relationship of Richoniella to the mushroom genera Leptonia and Entoloma. The truffle-like representatives cannot be differentiated from the epigeous ones on the basis of spores alone.

View photos of Richoniella spores

Sporocarp Characters

Shape and Size: Globose, subglobose to turbinate or irregular, 1-3 cm in diameter.
Peridium: White to pale pink, smooth or with fine, black rhizomorphs appressed near base and radiating root-like into the soil.
Gleba: White in youth, becoming pink to rosy as spores mature. With generally empty, labyrinthine chambers up to 1.5 mm long; columella lacking.
Odor: Not distinctive to potato-like or slightly pungent.

View photos of Richoniella sporocarps

Name Derivation

Named by Julien Noël Costantin (1857-1936) and Léon Marie Dufour (1862-1942) (1923) in honor of the French mycologist, Charles Eduard Richon, for his description of the first species in 1887 as a Hymenogaster. The diminutive Latin suffix -ella was appended because the name Richonia had already been used for an unrelated fungal genus.

Distribution

Richoniella species appear to be rare and are associated with Quercus in southern Europe, Arkansas, California, Florida, North Carolina, and Texas.
Season: Autumn.
Species known from North Temperate Forests: At least two and probably more; three species have also been described from the Southern Hemisphere.

Keys and Descriptions

Dodge and Zeller (1934) describe the two species known from the Northern Hemisphere. Dring and Pegler (1977) present a key to the five species described thus far from both Northern and Southern Hemispheres. Montecchi and Sarasini (2000) present European species.