Mycena acicula
Description
Mycena acicula is a species of fungus in the family Mycenaceae. It is found in Asia, the Caribbean, North America, and Europe. The fruit bodies grow on dead twigs and other woody debris of forest floors, especially along streams and other wet places. They have small orange-red caps, up to 1 cm (0.4 in) in diameter, held by slender yellowish stems up to 6 cm (2.4 in) long. The gills are pale yellow with a whitish edge.
Common names: Orange Bonnet, Coral Spring Mycena.
Mushroom Identification
Cap
The cap 2-10 mm broad, at first hemispherical, expanding to broadly-conic, occasionally with a low umbo, convex at maturity, not hygrophanous; margin weakly sulcate, striate to near the disc, incurved in youth, then decurved, sometimes slightly raised in age; surface reddish-orange shading to yellow-orange or pale-yellow at the margin; surface inconspicuously white-pruinose early in development; context thin, approximately 0.5 mm thick, creamy-yellow to pale yellow-orange; odor and taste not distinctive.
Lamellae
Gills adnate to notched, fairly well spaced, at first pinkish-cream, in age cream-yellow; edges even, not marginate; lamellulae in two to three series.
Stipe
Stipe 1.0-5.0 cm in length, 0.5 mm in width, equal, round, hollow, slightly viscid, white-pruinose over a translucent lemon-yellow ground color, becoming whitish, sparsely pruinose near the base, the latter with anchoring pallid hairs; partial veil absent
Spores
Spores 8.5-11.5 x 3.0-4.0 µm, narrowly elliptical to subfusoid in face-view; in profile narrowly elliptical, inequilateral with a straight and curved side; smooth, thin-walled, hilar appendage conspicuous, inamyloid; spore deposit not seen, presumably white.
Spore Print
White.
Habitat
Solitary to scattered in moist, shaded habits; fruiting on hardwood and conifer litter, sometimes among mosses and liverworts, but not attached; Coast Ranges and Sierra Nevada; fruiting from late fall to mid-winter along the coast, fall and spring in the mountains; fairly common.
Look-Alikes
Mycena adonis, Mycena floridula, and Mycena leptophylla
Larger species of the section Adonidae in the genus Mycena. In that section, among other differences, the hyphae of the cortical layer (the outer layer of tissue) of the stem are smooth.
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Similar in appearance to M. acicula, but the cap is yellower, the gills are broadly adnate or decurrent with a short tooth, the gill edge is orange to bright yellow, and the stem is dry, not sticky. The hyphae of the cortical layer of the stem are smooth and not embedded in gelatinous matter, and in European collections, the basidia are two-spored and do not have clamps.
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The North American and European species, look similar with their orange cap, but may be distinguished microscopically by the cheilocystidia which are densely covered by excrescences; it also has a larger cap, up to 2 cm (0.8 in).
Mycena aurantiidisca
Can be distinguished by the reddish-orange cap which tends to become paler at the margin.
History
First named Agaricus acicula by the German scientist Jacob Christian Schäffer in 1774, the species was also referred to as Agaricus miniatus by another German, naturalist August Batsch. It was given its current name in 1871 by Paul Kummer. Rolf Singer transferred the species to the genera Hemimycena and Marasmiellus, but the binomials resulting from these transfers are now considered synonyms. The fungus is classified in the section Aciculae of the genus Mycena.
The specific epithet acicula is derived from the Latin word meaning "small needle".
Photo sources:
Photo 1 - Author: Arne Aronsen/Naturhistorisk museum, Universitetet i Oslo (CC BY-SA 3.0)
Photo 2 - Author: Ron Pastorino (Ronpast) (CC BY-SA 3.0)
Photo 3 - Author: Nina Filippova (CC BY-SA 4.0)
Photo 4 - Author: Dan Molter (shroomydan) (CC BY-SA 3.0)
