Kudzu: The Green Shadow Over the South
July 18, 2025
Mushroom Monday: Flat-cap Agaric (Agaricus placomyces)
Introduction
The Flat-cap Agaric, Agaricus placomyces, is a mushroom found in woodlands and shaded areas beneath trees in eastern North America. It occurs in both natural forests and under ornamental or landscape plantings.
Overall Appearance
This tall mushroom features a broad, dry cap measuring 6 to 14 cm across. The cap is usually darker brown at its center and may display fine scales. As it ages, the cap flattens and can develop a pinkish tint when wet. Rubbing or bruising the surface often produces a yellowing reaction.
Cap and Gills
The brown-pigmented cap overlies a white flesh. Initially convex, the cap spreads out with maturity. Below, densely packed gills hang free from the stem. They begin white, shift to pink, and eventually turn brown. In younger specimens, a partial veil can cover the gills.
Stem Description
Standing 7 to 11 cm tall, the stem is smooth and occasionally slightly enlarged at its base. A white ring remains around the stem, a leftover from the partial veil.
Distribution and Habitat
Agaricus placomyces is documented throughout eastern North America. It grows saprophytically, drawing nutrients from organic material in the soil beneath both forest and landscaped trees.
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