Hysterangium coriaceum

A hypogeous fungus subglobose to ellipsoidal, 1.5 to 3 cm in diameter, white, developing pinkish to reddish-brown tones upon rubbing or handling, with a separable, fragile peridium that reveals its greenish-grey interior, and with a distinctly pleasant, fruity odor reminiscent of raspberries when mature.

My thanks to Pablo Chacón for providing the specimens for study.

Cuticle with an outer layer of large, globose hyphae, difficult to measure, deformed by mutual compression, hyaline and thin-walled.

Beneath these hyphae, the inner layer of the peridium features filamentous, densely interwoven hyphae, 2 to 4 µm in diameter, with abundant encrusting reddish-brown intracellular pigment responsible for the color change when rubbed.

Internal glebal hyphae hyaline, thin-walled, branched, 1 to 3 µm wide, embedded in a gelatinous matrix.

Basidia cylindrical-clavate, tending to collapse readily, hyaline, 25 to 40 µm long, 8 to 14 µm wide, with basal clamp connections, usually four-spored, though exceptionally bearing up to 6 or 8 spores.

Spores cylindrical-ellipsoidal to slightly fusiform, smooth, hyaline, thin- to very slightly thick-walled, 11 to 15 µm long, 3.5 to 5 µm wide, with an inconspicuous apiculus at one end, containing oil droplets of varying size inside, and inamyloid in Melzer's reagent.

Herbarium material available: JTP2793/26.