Cortinarius birkebakii Ammirati, Niskanen & Liimat., Index Fungorum 196: 1 (2014) [MB#550822]
Cortinarius birkebakii is a distinctive all-red species in sub-genus Dermocybe. Contrary to expectations, red Cortinarii are not in the same section or even in section Dermocybe – the coloration has appeared indpendently in different lineages.
Pileus: 9-30 mm across, red-brown with darker blackish red at center of disc, streaked. Stipe: Tan with striations of pinkish red. Gills: Deep burgandy to very dark red, later cocoa brown with red margins. Stipe: 25-55 mm tall, 2-5 mm wide at stipe apex, equal to slightly clavate, pinkish red with red-brown fibrils, more red to red brown at stipe base. Flesh: Pinkish red, lighter red in stipe apex, bruising darker where handled. Basal mycelium: Not observed but type description assumes orange. Habitat: Mixed conifer forest. Known from WA, BC and Oregon.
Consider Cortinarius birkebakii when you find a slender all-red Cortinarius in the Western USA. You will need to differentiate from Cortinarius neosanguineus which has the same stature but a brighter red to purple-red stipe and cap color and darker red-purple flesh. In C.birkebakii the cap appears more red-brown to burgandy and the stipe surface is pinkish, with darker red-brown fibrils, while flesh in stipe apex appears more pink, In C.neoganguineus ocher-yellow basal mycelium is often visible. Despite these features, I will admit Dermocybe are just plain hard to ID to species and it can be difficult to differentiate these species. Adding to difficulty is the fact that coloration varies with conditions – C.birkebakii can appear more vivid red in moist conditions and C.neosanguineus appear more dull in dry weather. Microscopically, spores are reported to be slightly smaller on average in C.birkebakii (7-8.4 x 4.1-5 microns vs 7-9 x 4.5-5.5 microns), but the difference is subtle.
Genbank reference of Type species: KP087973. Cortinarius birkebakii is not in Section Sanguinei, instead having a sister relationship to another red Dermocybe – Cortinarius idahoensis.
The following phylogeny shows a select number of North and South American species in sect. Dermocybe. It is interesting to see how red coloration has developed in several different lineages within the section. Cortinarius sanguineus, C.rubrosanguineus, C.sommerfleltii, C.idahoensis are all red Dermocybe species, as are C.smithii, C.harrisonii, C.marylandensis and C.sierraensis, not shown in this phylogeny.
>SDA661 Cortinarius birkebakii
Ammirati, J.F. T. Niskanen, K. Liimatainen, (2014), Index Fungorum no. 196. Effectively published 06/11/2014
Soop, K., B. Dima, J.A. Cooper, D. Park, and B. Oertel. “A Phylogenetic Approach to a Global Supraspecific Taxonomy of Cortinarius ( Agaricales ) with an Emphasis on the Southern Mycota.” Persoonia – Molecular Phylogeny and Evolution of Fungi 42, no. 1 (July 19, 2019): 261–90. https://doi.org/10.3767/persoonia.2019.42.10.