The cap is convex but flattens with age; it is typically 2 to 6 centimetres (0.8 to 2.4 in) wide. Cap margins are lightly to strongly rolled inwards.
Specimens have been found with the surface colors ranging from salmon-orange to pink to red. The cap surface typically has a conspicuous network of lightly colored ridges or veins that outline deep narrow grooves or pits – a condition technically termed sulcate or reticulate. The texture of the cap surface is gelatinous, although the internal flesh is firm, and pinkish in color. The gills have an adnate attachment to the stem, i.e., broadly attached to the stalk slightly above the bottom of the gill, with most of the gill fused to the stem; the gills are thick, packed close to each other, with veins and color similar to, but paler than the cap. The stem is 1.5 to 3.0 cm (0.6 to 1.2 in) tall by 0.4 to 0.6 cm (0.2 to 0.2 in) thick (usually slightly larger near the base), and may be attached to the bottom of the cap in a central or lateral manner. It is sometimes seen “bleeding” a red- or orange-colored liquid. The spore print has been described most commonly as pink, but also as cream colored. The species has no distinguishable odor, and a bitter taste.
The spores of R. palmatus are roughly spherical, with dimensions of 6–7.2 by 5.6–6.5 µm; the spore surface is marked with numerous wart-like projections (defined as verricose, in mycological jargon), typically 0.5–0.7 µm long The spores are non-amyloid, i.e., unable to take up iodine stain in the chemical test with Melzer’s reagent. The spore-bearing cells, the basidia, are club-shaped and 4-spored, with dimensions of 33.6–43.2 by 5.6–8 µm. Although this species lacks sterile cells called pleurocystidia (large sterile cells found on the gill face in some mushrooms), it contains abundant cheilocystidia (large sterile cells found on the gill edge) that are 27.2–48 by 4.8–8 µm in size. Clamp connections are present.
The content for this page is adapted from the Wikipedia article which was contributed to by Sasata. See that article for detailed references, authorship and references.