What You Should Know
Marasmius siccus is a small, saprobic basidiomycete orange to pale orange mushroom. It can be found growing in groups on leaf litter or dead hardwoods. The species has a large geographical distribution and can essentially be found coast to coast in the United States. The cap appears distinct due to pleats running down the length of the cap. The stem is distinct compared to other mushrooms because the stem is very thin and composed of hard tissue that isn’t malleable.
The gills and flesh below the cap are white; the gills attach to the stem. The color of the stem becomes lighter as the stem approaches the cap.
Other "pinwheel" Marasmius species include Marasmius rotula and Marasmius capillaris, with white caps; Marasmius pulcherripes, with a pink cap; and Marasmius fulvoferrugineus, with a rusty brown cap. The orange color of Marasmius siccus fades in age or dry weather; then it has less distinctive colors.
Although nonpoisonous, they are too small to be considered worthwhile as food.
Other names: Orange Pinwheel.
Marasmius siccus Mushroom Identification
Saprobic on leaf litter and woody debris in hardwood forests (and sometimes on the needle duff of white pine); usually growing gregariously; summer and fall; widely distributed east of the Rocky Mountains.
5-30 mm; cushion-shaped or bell-shaped, with a knob or a central depression; conspicuously pleated; smooth or minutely roughened; dry; bald; orange when fresh, fading to pale orange.
Attached to the stem or free from it; very distant; white to pale yellowish.
2.5-6.5 cm long; about 1 mm thick; equal; dry; wiry; whitish or yellowish above, brown toward the base; bald; basal mycelium white.
Odor and Taste
Taste mild or slightly bitter; odor not distinctive.
KOH on cap surface negative.
Spores 15-23.5 x 2.5-5 µ; smooth; spindle-shaped, cylindric, or club-shaped; inamyloid. Pleurocystidia cylindric, clavate, fusiform, or fusoid-ventricose; to about 70 x 15 µ; thin-walled. Cheilocystidia as dextrinoid broom cells. Pileipellis hymeniform, with dextrinoid broom cells.
Photo 1 - Author: Michael Hodge (Attribution 2.0 Generic)
Photo 2 - Author: David Heise (Attribution-NonCommercial 2.0 Generic)
Photo 3 - Author: Dinesh Valke (Attribution-ShareAlike 2.0 Generic)
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