Tricholoma scalpturatum, commonly known as the yellowing knight, is a species of agaric fungus in the family Tricholomataceae. It is a member of the genus Tricholoma, which consists of mushrooms characterized by white spore prints and a sinuate (notched) gill attachment to the stem.
Description
The fruit body of Tricholoma scalpturatum features a cap that typically ranges from 3 to 8 centimeters in diameter. Initially conical or convex, the cap flattens with age, often retaining a small central bump known as an umbo. The cap surface is dry and covered in fine, grey to brownish-grey fibrillose scales.
The gills are crowded and white to pale grey when young. A defining macroscopic characteristic of this species is the tendency of the gills and cap margins to turn yellow as the specimen matures or upon bruising. The stem (stipe) is cylindrical, measuring approximately 3 to 6 centimeters in length and 0.5 to 1.5 centimeters in diameter. It is generally whitish or light grey and may become hollow in older specimens. The spore print is white, and the spores are ellipsoid and smooth.
Taxonomy
The species was formally described by the Swedish mycologist Elias Magnus Fries in 1838. The specific epithet scalpturatum originates from the Latin word for "scratched" or "engraved," referring to the textured, scaly appearance of the cap.
Distribution and Habitat
Tricholoma scalpturatum is widely distributed across Europe and has been recorded in parts of Asia. It is a mycorrhizal fungus, forming symbiotic relationships with various tree species. It is frequently found in deciduous forests, particularly with Tilia (lime), Quercus (oak), and Fagus (beech), but it also occurs in coniferous woods. The species is notably common in anthropogenic habitats such as parks, gardens, and urban green spaces. It typically fruits from late summer through late autumn.
Odor and Edibility
The mushroom possesses a distinct farinaceous (mealy) odor and taste, resembling fresh flour or watermelon rind. While it is generally considered edible in many mycological guides, it is often avoided by foragers due to its resemblance to other grey-capped species within the Tricholoma genus, such as the poisonous Tricholoma pardinum or the similarly appearance-wise Tricholoma terreum. Accuracy in identification is required to distinguish it from toxic relatives.