Fleshy Fungi of New Brunswick >> Cortinarius mucosus

Cortinarius mucosus (Bull.) J. Kickx f.

Scattered to gregarious (11) in sandy soil in a mature plantation of Pinus banksiana, NE of Utopia, New Brunswick (04-10-20/01).

Pileus broadly conic-convex at first, more broadly so at maturity and finally nearly plane, without an umbo, smooth, with margin becoming uplifted in age, strongly viscid, glabrous, orange brown (HSV25:90:60-70) at the centre and paler and more yellow (HSV35:40-50:90-100) elsewhere, 38-80 mm in diameter. Stipe equal, slightly tapered at the extreme base, very pale yellow to white above the annular zone at first but with this region later becoming light orange (HSV35:50:90), peronate below the annular zone with the viscid white universal veil, with veil easily removed and revealing a ground colour similar to that of the stipe apex, glabrous, 65-130 x 8-14 mm. Lamellae nearly white to pale rusty brown at first, close, adnexed, not marginate. Cortina very sparse, white. Flesh concolourous with the pileipellis in the subpellar 0.5 mm, white to faintly yellow elsewhere, lacking a distinctive odour and taste, not bitter.

Basidiospores reddish brown in spore print, fusoid, usually with a pronounced apical umbo and a suprahilar depression, coarsely roughened, 11.5-13.7 x 4.9-5.8 µm, Q = 2.17-2.56 (average[41]: 12.8 x 5.3 µm, Q = 2.40). Cheilocystidia forming a continuous sterile margin, clavate, with a basal clamp connection, with few or no conspicuous cytoplasmic inclusions in water, Windex, or KOH mounts, 18-34 x 8.3-12.5 µm (average[14]: 26.1 x 10.1 µm). Basidia clavate, 4-spored, with a basal clamp connection, usually with a large refractive cytoplasmic inclusion and one or more smaller ones, 36-44 x 9.3-11.2 µm. Pileipellis an ixocutis overlying a thin subcutis, with gelatinous layer ranging from 25 µm deep near the pileus margin to 170 µm deep near the centre, with hyphae bearing clamp connections.

Recognized by its orange brown viscid pileus, white viscid stipe, flesh with a mild (not bitter) taste and association with pines. Microscopically it is characterized by its large and very narrow basidiospores (Q > 2.0), small cheilocystidia and abundant clamp connections. It is known in both Europe and North America. Cortinarius collinitus is very similar but differs in a less strict association with pines and in having much broader basidiospores.

Photograph: D. Malloch (04-10-20/01).