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Species Information
Summary: Features include a cup with an incurved margin, blackish inner surface, black and wrinkled outer surface often with fine orange granules near the margin, tough flesh, absent stem or a short narrowed base, growth on sticks and other debris of both hardwoods and conifers in spring, and microscopic characters including elliptic or spindle-shaped spores and inamyloid asci.
Plectania melastoma is found at least in BC, WA, OR, ID, CA, and CO, (Larsen), WA, MB, ME, United Kingdom, West Indies, Australia, and New Zealand, (Seaver), ME to BC, south to FL and Mexico, (Lincoff), and Denmark, Finland, Norway, and Sweden, (Hansen).
Upper surface: 1-2.5cm across and 1-3(4)cm high, at first nearly spherical, becoming cup-shaped, margin usually incurved for a long time but sometimes splitting in places; spore-bearing upper surface black or deep brownish black, smooth or sometimes with vein-like markings when dry, "often glistening when wet", (Arora), up to 3cm across, cup-shaped, black or nearly black, (Castellano), up to 2cm, inner surface permanently concave, black, (Dennis), margin delicately dentate (Hansen)
Flesh: tough or cartilaginous, not brittle, "but with a semi-gelatinous inner layer when wet", (Arora), tough outside, with interior gelatinous layer, (Seaver), relatively thick-fleshed but interior not gelatinous, (Castellano), gelatinous (Lincoff)
Underside: black, but often with rusty-orange near margin from minute orange granules; "minutely hairy, strongly wrinkled or veined", (Arora), when young, may have orange to rust-colored granules around rim, (Castellano), black, minutely downy with hairs that are encrusted with red granules especially near margin, (Dennis)
Stem: absent or a short stout narrowed base, colored like exterior and continuous with it, "the base often with wiry black mycelial threads that extend into the substrate", (Arora), sessile to subsessile (Castellano), rudimentary stem, subiculum of slender wiry black mycelium, (Dennis), when present 0.5-1cm long and wide, (Lincoff)
Microscopic: spores 20-28 x 8-12 microns, elliptic or spindle-shaped, smooth, with oil droplets when immature, (Arora), spores 21-24 x 8-10 microns, elliptic, smooth; asci long, narrow, with curving base, thick-walled, operculate, inamyloid; paraphyses "up to 4 microns wide, branched, anastomosing around asci", (Castellano), spores 23-28 x 10-11 microns, fusiform, smooth, at first containing many oil droplets which disappear when mature, uniseriate; asci up to 450 x 12 microns; paraphyses slender, repeatedly forked, brown; hairs closely septate with thin walls that are often encrusted with red granules, (Dennis), hairs long, about 7 microns wide, brown, flexuous [wavy], often interspersed with brick-red granules, (Seaver), spores 23-28 x 10-11 microns, spindle-shaped, smooth, containing many oil droplets which disappear when mature, (Lincoff), spores 20.5-24 x 10-12 microns, elliptic, with irregular low fine warts (illustrated), with 2 or more droplets, (Hansen), spores are warty (Trudell)
Habitat / Range
single or more often in small groups or clusters "on decaying sticks and other debris of both hardwoods and conifers", mainly fruiting in spring, (Arora), usually associated with decaying woody debris of relatively small diameter (often less than 7.5-10cm), fruiting in spring, (Castellano), single to clustered in conifer debris, May to June, (Lincoff), among mosses on twigs of coniferous trees, or on soil, rarely on Calluna or Corylus; (fall-) spring to early summer, (Hansen for Scandinavia)
Similar Species
Plectania milleri has a stellate margin (with star-like points), and no orange granules, (Arora). P. milleri "differs from P. melastoma in its stellate margin, dark hyphae penetrating the medullary excipulum, and smooth tomentum hyphae. In P. melastoma the margin is entire or slightly split but is never stellate, the tomentum hyphae are encrusted with orange granules, and there are no dark hyphae in the medullary excipulum", (Paden). Pseudoplectania nigrella and Pseudoplectania melaena have round spores and no orange granules. See also SIMILAR section of Donadinia nigrella.
