Cortinarius mikedavisii Bojantchev
Notes: STB 20 Jun 2013
Source: Mycotaxon, 118: 267, 2011 [MB#561221]
Family: Cortinariaceae
Cortinarius mikedavisii image
Dimitar Bojantchev  
Mycotaxon
D Bojantchev. 2011. Cortinarius mikedavisii sp. nov. from northern California. Mycotaxon 118: 265–272.

Cortinarius mikedavisii Bojantchev, sp. nov. Figs 2–6 MycoBank MB 561221

Pileo 60–220 mm lato, hemispherico, dein planoconvexo, planoconcavo, glutinoso, roseobrunneo, cum KOH purpureobrunneo, margine involuto. Lamellis emarginatis, caesiis dein flavidis, purpureobrunneis, in statu senili. Stipite 50–140 mm longo, cylindrico, bulbo marginato, 30–50 mm lato. Velo universale roseobrunneo. Velo partiale copioso, flavido. Carne caesio dein albido. Sapore miti. Sporis 10–13 × 6–7 μm, amygdaliformibus, verrucosis, basidiis 28–42 × 8–9 μm, tetrasporigeris, fibulis praesentibus.

Type: USA. California: Mendocino County, Caspar, Caspar Cemetery, under Picea sitchensis, 27 Nov 2010, Bojantchev DBB40100 (Holotype UC 1860820; Genbank nrITS JF795384).

Etymology: In honor of Prof. Mike Davis whose encouragement and support in the area of molecular genetics made these Cortinarius studies possible.

Stature pileocarpous bulbopodium. Pileus 60–220 mm diam., hemispherical to convex when young, plano-convex to plano-concave at age; margin involute then straight; colors intense, mostly reddish to orange brown on the disk, varying from carmine brown to rose brown (10R 3/6–4/8), paler on the margin, copper brown to sulphur yellow (10R 6/8–7.5YR 7/8); surface very glutinous when wet, glabrous to dull glossy when dry. Lamellae crowded, 10–22 mm broad, blue (GLEY2 6/10G–8/10G) at first, turning olive (5Y 6/4–8/4) then yellowish clay (5Y 8/6–8/8) with purplish tinges, then purplish brown as the spores mature; edge even; attachment sinuate; lamellulae abundant. Stipe 50–140 mm long, 15–30 mm wide, cylindrical to subclavate above the bulb, pale yellow, with rose brown streaks from universal veil. Bulb 30–80 mm diam at the widest point, well-developed, abruptly emarginate, tapering below, rose to purplish brown around margin; the subterrestrial part with a pale to sulphur yellow cottony mycelial felt and rhizomorphs. Universal Veil rose to purplish brown, leaving copious remnants on the pileus and bulb margin. Cortina yellow, leaving an annular zone of dense fibrils on the stipe. Context white to bluish at first, paling to white at maturity with yellow tinges in the bulb. Odor earthy. Taste mild, earthy. Macrochemical Reactions 5% KOH strong and complex, dark purple red on the pileus; on the context pale olive at first, soon lilac on pileus context, strongly purplish on bulb context and paler on stipe context. Spore Deposit deep rusty brown.

Basidiospores (9.5–)10.5–13.2(–15.5) × (5.7–)6.2–7.2(–7.8) μm (mean 11.5 × 6.7 μm), Q = 1.61–1.78, Qav = 1.72 (N = 178, 7 basidiomata, four collections), amygdaliform, some with apical papilla, strongly verrucose. Basidia 28–42 × 8–9 μm, 4-spored, cylindro-clavate, clamped. Gill edge sparsely fertile. Cystidia not observed. Pileipellis an ixocutis, simplex, no hypodermium detected, composed of parallel to interwoven hyphae in a dense gelatinous matrix 230–300 μm thick, made up of 4–12 μm wide, irregular hyphae, with greenish to purplish intracellular pigment when mounted in 5% KOH. No distinct reactions to Melzer’s reagent were observed. Clamp connections common in all parts.

Habitat and distribution — Cortinarius mikedavisii appears to be an uncommon species. Currently it is known from only three locations, at two of which it fruits regularly. The habitat is mixed woods with Sitka spruce (Picea sitchensis (Bong.) Carrière) being the one common symbiont in all locations. The author has never seen it south of Mendocino. Its distribution appears to be limited to northern California and southern Oregon, where it was collected once. There are no matching records from Washington and British Columbia despite the intensive collecting and molecular cataloguing that has taken place in these regions.

Cortinarius mikedavisii image
Dimitar Bojantchev  
Cortinarius mikedavisii image
Dimitar Bojantchev  
Cortinarius mikedavisii image