Cortinarius sierraensis (Ammirati) Ammirati, Niskanen & Liimat.
Mycologia 105(2): 353. 2013.
Common Name: none
Synonym: Dermocybe sierraensis Ammirati
Cap 20-40 mm broad, convex-umbonate, expanding to plane, often with a low umbo; margin incurved, becoming decurved, lacking veil remnants; surface dry, appressed fibrillose, reddish-brown orange, the color arising from reddish to vinaceous fibrils streaked over an orange-brown background; context to 3 mm thick near the disc, soft, vinaceous pink, unchanging; odor and taste mild.
Gills notched, close to subdistant, relatively broad, 4-6 mm in width, dark reddish-brown throughout development, edges even; lamellulae in up to 3 series.
Stipe 20-50 x 4-6 mm in width, cylindrical to tapered slightly to bent towards the base, stuffed to hollow; surface dry, silky fibrillose, colored like the cap; context concolorous with cap context; partial veil evanescent, of scattered reddish to vinaceous brown fibrils over a pale pinkish background; reddish-brown mycelium at the base.
Spores 7.5- 9 (10) x 5-5.5 µm; more or less ellipsoid in both profile and faceview, slightly warted at 1000X, lacking a germ pore, hilar appendage not apparent, inamyloid; spores dull brown in deposit.
Scattered, in small groups, occasionally clustered, under conifers, especially lodgepole pine (Pinus contorta ssp. murrayana) at higher elevations of the Sierra Nevada; uncommon.
This attractive but uncommon montane Cortinarius, formerly known as Dermocybe sierraensis, is recognized by a reddish-brown to orange brown appressed fibrillose cap, deep reddish brown gills, and stipe colored like the pileus. Closely related Cortinarius neosanguineus known from Mendocino northward in coastal forests differs in possessing a dark red to purplish red cap, reddish to pale reddish stipe with yellowish red mycelium at the base. Additionally, it typically occurs with conifer genera other than pine, i.e. Tsuga, Pseudotsuga, Abies, and Picea. Other brightly colored, primarily reddish Cortinarius species include Cortinarius smithii, formerly known as Cortinarius phoeniceus var. occidentalis, with a dark red cap and gills, but a yellowish stipe and Cortinarius semisanguineus, with a yellowish brown cap and stipe and dark red gills; finally Cortinarius californicus is a reddish species of north coastal forests readily distinguished by a strongly hygrophanous cap.
Ammirati, J.F. (1989). Dermocybe, sugenus Dermocybe, section Sanguineae in Northern California. Mycotaxon 34: 21-36.
Niskanen, T., Liimatainen, K., Ammirati, J.F. & Hughes, K. (2013). Cortinarius section Sanguinei in North America. Mycologia 105(2): 344-356. (Abstract) (PDF)