Cortinarius rubellus
deadly webcap
Cortinariaceae

Species account author: Ian Gibson.
Extracted from Matchmaker: Mushrooms of the Pacific Northwest.

Introduction to the Macrofungi

Photograph

© Michael Beug     (Photo ID #18518)


Map

E-Flora BC Static Map

Distribution of Cortinarius rubellus
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Species Information

Summary:
Section /Orellani. Features include 1) a non-hygrophanous or slightly hygrophanous cap that is dry, orange-brown to reddish brown, and woolly fibrillose to fibrillose-squamulose, 2) pale yellow flesh, 3) adnexed to sinuate gills that are yellow-brown to rusty brown, 4) a dry, yellow-brown to red-brown stem that is club-shaped or wider in the middle, and has yellowish veil bands, 5) a radish-like to indistinct odor and taste, 6) conifer habitat, and 7) warted, nearly round to ovate or elliptic spores.
Cap:
1.5-5.3cm across, bell-shaped to convex then flat-convex, more or less umbonate, sometimes conic, edge inrolled to incurved then downcurved to flat; not hygrophanous, evenly reddish brown to rust brown, "scales sometimes dark reddish brown"; surface sometimes rimose [cracked], dry, unpolished, fibrillose to velvety, sometimes minutely scaly on disc, margin even or sometimes crenate-sulcate [scalloped-grooved] or virgate [radially streaked] to rugulose [finely wrinkled], "margin sometimes decorated with veil fibrils", (Robertson), 4-5.5cm across, convex-umbonate, margin at first inrolled and sheathed by the cortina, when old decurved [downcurved]; "somewhat hygrophanous over disc, light orange-brown to reddish brown", "dry, woolly-fibrillose to fibrillose-scaly", (Thorn), 3-8cm, obtuse to convex, expanding to conic - bell-shaped, conic-umbonate, obtusely bell-shaped or broadly convex, sometimes nearly flat when old; "russet" (russet brown) on disc and "tawny" over marginal area, when fruiting luxuriantly even rich tawny to "Sanford's brown", unchanging or merely slightly darker when very old; "dry, innately fibrillose-squamulose over disc or nearly to margin", (Smith)
Flesh:
thin except on disc; pale yellow in cap and upper stem, with rusty stains near base, (Thorn), rather thick in disc, thin away from it; pale buff, (Smith)
Gills:
ascending to sinuate, close to subdistant (about 14 gills or subgills per centimeter) or distant (a comparison chart with other species gives gill spacing as distant), 0.3cm broad on average, ventricose; caramel, yellowish to yellow-brown, orange-brown, or reddish brown to dark rusty brown, sometimes with rusty brown spots, not bruising; "edges straight, even, entire", (Robertson), adnexed, subdistant, to 0.8cm broad, thin; at first brownish orange, then bright yellow-brown; not marginate, (Thorn), adnexed, subdistant, broad, thick and interveined; "ochraceous tawny", when young, soon "tawny" and remaining so; edges even, (Smith)
Stem:
3.5-8.2cm long, up to 1.5cm thick, base up to 1cm thick, club-shaped to bulbous, tapered or pointed in lower part, "becoming fusiform when mature, sometimes splitting at base"; dark reddish orange at top, base reddish brown, dark reddish orange to moderate reddish brown or rusty yellow orange, becoming yellow, with yellow to bright yellow brown veil bands, fibrils and cortina remnants bright yellow brown, "color not changing when bruised or bruising dark rusty at times"; at times longitudinally striate, base sometimes scaly, top flocculose, surface dry, (Robertson), 5-7cm x 0.9-2cm, club-shaped or ventricose [wider in middle], slightly rooting, solid, fleshy-fibrous; predominantly brownish orange, with rusty to reddish brown stains toward the base, and overlain with patches or bands of woolly yellow veil remnants toward the base; dry, silky-fibrillose, (Thorn), 5-8(10)cm x 1-1.2(1.5)cm, stuffed, pale to dark tawny, mycelium white, (Smith)
Veil:
stem overlain with patches or bands of woolly yellow veil remnant towards the base, cortina pale yellow with whitish inner fibrils, evanescent, (Thorn)
Odor:
"Radish/mild or radish" (Robertson), not distinct (Thorn), radish (Smith), mushroomy or slightly radish-like, (Lincoff), radish (Courtecuisse), radish (Courtecuisse)
Taste:
not distinct (Thorn), slight of radish, (Smith), sweet (Lincoff)
Microscopic spores:
spores (8.0)8.8-10.2(11.2) x (6.3)6.6-8.0(9.0) microns, broadly ovate or ovate-elliptic; basidia (2-) to 4-spored, 40-60 x 9-12 microns, clavate; cheilocystidia 15-35(43) x 5-12 microns, clavate, fusoid-ventricose, or phalloid, (Thorn(1)), spore shape and size variable, but most in the range 8.9-10.4(11.1) x 6.7-7.8(8.9) microns, distinctly ornamented, (Robertson(1) who note that this is smaller than reported for European specimens - 8-11 x 6.5-8.5 microns - but similar to Thorn(1) and Smith(9)), spores 9-11 x 6.5-8 microns, broadly ovate, roughened, dark rusty brown in KOH; basidia 4-spored, 38-52 x 8-10 microns, colorless in KOH (many brownish collapsed basidia also present); pleurocystidia none, cheilocystidia basidia-like but smaller at 30-40 x 5-8 microns, narrowly clavate to subcylindric and colorless or nearly so; "gill trama parallel or nearly so", yellowish (in thin sections) to rusty reddish (in thick sections) in KOH, cap characterized by fascicles of rusty brown to yellow-brown (in KOH) "hyphae projecting to form squamules, pigment incrusted on the wall but deposits not heavy, clamp connections present", (Smith for Cortinarius rainierensis), spores (8.7)9.1-10.0(10.8) x (6.7)6.9-7.9(8.3) microns, broadly ovate, finely warted; basidia 4-spored, clavate, 39-49 x 10-12 microns; "cheilocystidia present but inconspicuous, irregularly cylindric or clavate", 19-30 x 9-12 microns, (Thorn for Cortinarius rainierensis)
Spore deposit:
red-brown (Buczacki)
Notes:
Collections were examined from BC, WA, and Sweden, (Robertson). Harrower(1) assigned a BC collection sequence 66 to Cortinarius rubellus. Thorn examined collections of the synonym Cortinarius speciosissimus from ON, NS, ME, and Sweden. Garnica(1) used a collection of C. rubellus from Germany.
EDIBILITY
deadly poisonous, contains orellanine, (Benjamin)

Habitat and Range

SIMILAR SPECIES
Cortinarius gentilis has 1) a hygrophanous cap that is deep brownish yellow fading to pale yellow (also referred to as bright brownish yellow), often with a more or less acute umbo, the margin sometimes slightly striate, 2) distant gills that are brownish yellow and may have a dull olivaceous, dark reddish, or violaceous tinge, 3) a rather long, slender, cylindric stem with a base that is tapered or rooting, the stem surface yellow to yellow brown, darkening in the lower part, 4) a yellow veil thinly sheathing the stem and forming a distinct zone with thin girdles in the lower part, 5) an odor that is mild or of wet cement, raw potatoes, or radish, and 6) distinctly ornamented spores 7-8.5 x (5.5)6-6.5 microns, (Robertson). |Cortinarius limonius has 1) a hygrophanous cap that is red-brown, brownish yellow to reddish orange, fading to bright yellowish, 2) moderately crowded gills that are dark yellow to brownish yellow or ochraceous brown, 3) a cylindric to fusiform stem that is yellow to yellow brown, the veil pale yellow and forming indistinct zones, 4) mild odor, and 5) spores 7.5-8.5(9) microns, finely ornamented (as opposed to distinctly ornamented for Cortinarius rubellus), (Robertson). |Cortinarius callisteus has 1) a non-hygrophanous cap that is bright orange-yellow to reddish brown, often finely tomentose-scaly, especially near the center, 2) close to distant gills that are orange-yellow to yellow brown, 3) a clavate, sometimes rooting stem that is orange-yellow to reddish brown (reddish brown toward the base), and fibrillose to scaly, 4) stem interior often a reddish brown, 5) a peculiar odor of locomotive diesel or mild odor, and 6) moderately ornamented spores 8-10.5 x 6.2-8 microns, (Robertson). |Cortinarius orellanus (not documented from North America) 1) fruits in mixed or hardwood forests (rarely coniferous), 2) has a non-hygrophanous cap that is red-brown, orange-brown, or ochraceous brown, more dark brown when old, finely scaly, and thin-fleshed, 3) has distant gills that are warm ochraceous to rust-brown, 4) has an equal stem (with the base sometimes tapered) that is golden yellow to red-brown, and rather smooth, 5) has a veil that is slightly fibrillose, and pale yellow, 6) has an odor that mild or radish-like, and 7) has distinctly ornamented spores 8-10 x 6-6.5 microns, (Robertson). |C. limonius and C. callisteus both have non-umbonate or barely umbonate cap and brighter yellow or yellow-orange colors, (Breitenbach). |Cortinarius distans var. olympianus [synonymized here with Cortinarius hinnuleocervinus] has a hygrophanous cap with a margin that is faintly striatulate when moist, and distinctly narrower spores (5-6 microns), (Smith).
Habitat
gregarious to cespitose, under second generation young to mature Pseudotsuga menziesii (Douglas-fir) with Tsuga heterophylla (Western Hemlock), Thuja plicata (Western Red-cedar) and Acer circinatum (Vine Maple), also on very rotten moss-covered logs under Tsuga heterophylla and Thuja plicata; in BC and Washington from early July to later September, (Robertson), gregarious to cespitose in duff under Abies balsamea in the collection from Nova Scotia, subcespitose in Sphagnum under Larix laricina and Picea mariana in Ontario, and reported from wet, boggy sites in Europe, (Thorn), on humus in coniferous forest, (Smith), summer, fall

Synonyms

Synonyms and Alternate Names:
Cortinarius speciosissimus Kuehner & Romagn.