Tricholoma ustale

Morphological Features:

Pileus reaching up to 10 cm in diameter at maturity, and occasionally slightly exceeding this size. Initially hemispherical to somewhat conical, later becoming convex and finally flattened. The surface is separable and slightly viscid in wet weather; otherwise glossy but not viscid. Reddish-brown to chestnut-brown in color, somewhat darker centrally and fading toward the margin in many specimens. Cuticle smooth and radially fibrillose; margin regular, lacking striations and not grooved.

Lamellae sinuate, whitish to cream-colored. Upon handling, they develop reddish-brown tones, particularly evident on the edges. Moderately crowded, with lamellulae, straight.

Stipe frequently elongated, irregular in shape, sometimes clavate and at other times cylindrical, with a tendency to thicken toward the lower portion and taper at the base, which occasionally becomes radicate. The surface has a whitish background but is overlaid with longitudinal brownish fibrils, giving it a predominantly brown appearance to the naked eye, except perhaps at the apex. Lacks an annular zone demarcating the two colors.

Flesh thick and fibrous, white in color with a tendency to brown upon cutting, particularly in the stipe. It has a faint farinaceous odor and a taste that is initially farinaceous but becomes bitter after prolonged mastication.

Habitat:

This species occurs in various broadleaf forests; its presence under conifers has not been documented. It fruits primarily during autumn in small groups on the ground, though it may occasionally appear at other times of the year. Relatively common but not abundant.

Observations:

This species is characterized by a weakly viscid pileus surface, a stipe lacking clear demarcation between two colors, and a farinaceous taste that becomes bitter upon prolonged mastication. Tricholoma ustaloides has a markedly viscid pileus and a stipe with well-defined color demarcation; additionally, its flesh is promptly bitter. Tricholoma fulvum is also similar, possessing yellowish lamellae when young and a grooved pileus. There are many other brown Tricholoma species, such as Tricholoma stans, which is very similar but associated with conifers, among others. Careful examination allows for their macroscopic differentiation.