Pluteus atromarginatus: The Ultimate Mushroom Guide
About The Pluteus atromarginatus Mushroom
Pluteus atromarginatus is a dark-brown mushroom with a slightly umbonate cap that fades to greyish-brown, the surface streaked with dark fibrils, and free gills with brown edges, i.e. marginate. Though rarely collected for the table, it should be noted that some Entoloma species, many of which are toxic, are similar in stature and also have pink spores. They can be distinguished by attached gills, a terrestrial, not lignicolous habit, and angular spores.
Like all species of Pluteus, this handsome mushroom is a wood-rotting saprobe with a pink spore print and gills that are free from the stem. Unlike most other Pluteus species, however, it has "marginate" gills: the edges are dark brown or black, while the faces are pale at first and, with maturity, pink. Other distinguishing features include its preference for conifer wood, its dark brown colors, its fairly large size, and its microscopic features (see below).
This fungus is reported to be edible, but because of its rarity, this mushroom should not be gathered for eating.
Other names: Blackedge Shield.
Pluteus atromarginatus Identification
4 to 7cm across; initially convex, developing a slight umbo while flattening; margin remaining downcurved; dark brown to almost black, with adpressed radial fibrils; center sometimes finely scaly.
Free; crowded; white with black or dark brown edges; gill faces turning pink as the spores mature.
5 to 12 cm long and 0.5 to 1cm diameter, often with a slightly swollen base; smooth white surface, sometimes with dark brown or black longitudinal fibers; no stem ring.
Broadly ellipsoidal or subspherical, smooth, 6-8 x 4-5µm.
PLeurocystidia on the gill faces are lageniform, typically 80 x 20µm, and project well beyond the basidia; as they mature they become ornamented with two, three, or sometimes four apical 'horns'.
Odor and Taste
Habitat & Ecological Role
In common with other shield mushrooms, this is a wood-rotting (saprobic) fungus, but this species is unusual in being restricted to softwoods (timber of coniferous trees). Blackedge Shields tend to be either solitary or at best occurring in very small groups.
Pluteus atromarginatus Look-Alikes
Has a smooth, paler brown or fawn cap and lacks the dark edge to its gills.
Is very similar, though it is currently known only from the Great Smoky Mountains National Park. Its fibrils and scales are "more loosely arranged" (Justo et al., 2014), its spores are very slightly smaller, and its pleurocystidia have only two hooks.
Pluteus atromarginatus Taxonomy & Etymology
This distinctive woodland mushroom was described in 1925 by German-born American mycologist Rolf Singer, who gave it the scientific name Pluteus cervinus var. atromarginatus. French mycologist Robert Kuhner (1903 - 1996) raised its status to species level in 1935, thereby establishing its scientific name as Pluteus atromarginatus.
Synonyms of Pluteus atromarginatus include Pluteus cervinus var. nigrofloccosus R. Schulz, Pluteus cervinus subsp. atromarginatus (Singer) KÃ¼hner, Pluteus tricuspidatus Velen., and Pluteus nigrofloccosus (R. Schulz) J. Favre.
Pluteus, the genus name, comes from Latin and means a protective fence or screen - a shield for example! The specific epithet atromarginatus means 'with a black edge or margin' - a reference to the dark edge of the gills.
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