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Species Information
Summary: Section Ochroleuci (Vibratiles). Features include 1) a slimy, orange-ocher to reddish brown cap that is finely pruinose from a white veil when young, the veil remaining for a long time toward the margin, 2) notched gills that are cream-colored when young, 3) a viscid, light brown stem that is white fibrillose when young, 4) mild to bitterish-tasting flesh but a bitter cuticle, and 5) microscopic characters including narrowly elliptic, finely verrucose spores. The description is derived from Breitenbach(5) except where noted.
Harrower(1) assigned a BC collection sequence 52 to Cortinarius causticus. Morphological correlation is desirable. Kroeger(5) reported it from Haida Gwaii in BC. The accompanying photograph is from WA. Distribution includes Europe and North Africa (Breitenbach(5)).
Cap: 3-6cm across, hemispheric when young, becoming convex to flat with obtuse umbo "and at times somewhat undulating", margin even and acute; "finely pruinose on an orange-ocher background from a white veil when young", later becoming bald and orange-brown to reddish brown, paler to whitish toward margin; smooth, "slimy and shiny when moist, dull when dry", margin sometimes barely striate, (Breitenbach), 3-5(6)cm across, reddish brown to orange-foxy, when young covered by a whitish veil, later pruinose, (Moser)
Flesh: thin; whitish, (Breitenbach), white (Moser)
Gills: "notched and narrowly attached", broad, 42-53 gills reaching stem, 1-3 subgills between neighboring gills; cream becoming ocher brown to rust brown; edges +/- smooth
Stem: 5-8cm x 0.7-1.5cm, cylindric with slightly bulbous base or clavate [club-shaped], "solid to pithy-hollow, flexible"; "white-fibrillose on a light brown background from a viscid to somewhat slimy veil when young", later becoming bald "and sometimes developing a faint annular zone and becoming white-pruinose above it", (Breitenbach), 3-4cm x 0.6-1cm, equal or base tapering, whitish ocher, (Moser)
Veil: cap pruinose at first from white veil, stem white-fibrillose from a viscid to somewhat slimy veil at first
Odor: sourish, fungoid
Taste: mild to bitterish, cuticle very bitter, (Breitenbach), only cap skin bitter (Moser)
Microscopic spores: spores 5.5-7.2 x 3.5-4.2 microns, elliptic, "indistinctly and densely finely verrucose, pale yellow"; basidia 4-spored, 25-31 x 5.5-6.5 microns, slenderly clavate, with basal clamp connection; no pleurocystidia seen, marginal cells 15-30 x 4.5-6.5 microns, polymorphic; septa with clamp connections, (Breitenbach), spores 6-8 x 3-4 microns, (Moser), spores 4.5-5 microns wide (Brandrud et al. per Breitenbach(5))
Spore deposit: [presumably a shade of brown]
Habitat / Range
usually gregarious to clustered under conifers or hardwoods on poor, sandy soils, especially under Picea (spruce) and Pinus (pine), summer to fall, (Breitenbach for Europe), coniferous woods or hardwood woods (Moser)
Similar Species
Cortinarius vibratilis is bitter in all parts, and spores are wider at 6-7.8 x 4.2-5 microns (but note Brandrud et al. above),(Breitenbach(5)). C. vibratilis has lighter colors than C. causticus, (E. Harrower, pers. comm., via K. Luther). C. causticus has a distinct granular cap surface: when you lick it to check for bitter slime it feels pebbled like curling rink ice. The umbo also tends to be flattened and broad, and the whole stature is more robust than C. vibratilis which has a more pointed but smoother cap. (P. Kroeger, pers. comm.). Cortinarius crystallinus is bitter in all parts (Moser(1)).
