Texas Yellow Caps

Habitat and distribution

The fruit bodies of B. curtisii grow singly, scattered, or in small groups on the ground in coniferous or mixed woods, often with pines. Fruit bodies generally appear from August to November. The geographical distribution of the fungus is limited to eastern and southern North America. In the United States, it occurs from New England south to Florida, and west to Texas. The species was newly reported from Mexico in 2001.

Pigments

The fruit bodies of Boletus curtisii contain a unique series of derivatives of the molecule canthin-6-one. Before this discovery, canthin-6-one alkaloids were only known from higher plants. Among the canthin-6-one derivatives are the pigments that give the mushroom its bright yellow color, including two optically active sulfoxides named curtisin and 9-deoxycurtisin. Spraying a fruit body with methanol causes the pigments to dissolve and makes the color wash away—a phenomenon unknown in other bolete mushrooms. Additionally, spraying fruit bodies with acetone results in a green-yellow fluorescence visible in daylight.