Cortinarius aff. atrosquamosus

Cortinarius aff. atrosquamosus Niskanen, Liimat., Peintner, Kuhn.-Fink. & Ammirati, Persoonia 46: 230 (2020)

Description

PILEUS: 22- 68 mm across, convex to plane, surface velvety, tomentose scaly, black to dark brown to olive, some specimens are dark to margin when young, dark scales on disc and olive towards margin when expanded. GILLS: olive-yellow to tan.  STIPE: 27 – 104 mm long, 6-13 mm thick at apex, equal to slightly swollen base, cream to dull yellow-brown. CORTINA: Observed as white sheath on lower stipe when young, later patches of cream to olive-brown material on stipe. FLESH: Firm, solid, creamy white to straw yellow with darker core (dull olive brown or brown). UV: Yellow on flesh and gills when fresh, UV patchy on upper stipe and cap surface, more faint and varied UV reaction on dried specimens.

ECOLOGY: Solitary / scattered in conifer and conifer broadleaf forests in Western North America. To date, known from Northern California to B.C.

Photographs

The following images are of collections which have slight genetic difference to Cortinarius atrosquamosus but no consistent morphological difference has been identified so far.

Discussion

Recent work on Cortinarius section Leprocybe (Ammirati et al, 2020) has described many new species and given us new insight on the diversity of North American species. One of these is Cortinarius arosquamosus. The paper includes discussion of SDA357 and SDA421 which are not identical, but close to the type. Intraspecies ITS variation is relatively high (0.7%) in this species. However, since there were no consistent morphological differences observed between collections, the group is left without further differentiation (see below for phylogenetic comparison).

In the past, this species was likely identified as Cortinarius clandestinus. Since this is the most familiar Leprocybe in the Pacific Northwest, it is important to figure out how to differentiate C.atrosquamosus from this species in the field. Unfortunately, there is no clear answer. Several of my collections of C.atrosquamosus (like the type photograph in the paper) have dark black to olive-brown scales covering the entire cap which is not something seen in C.clandestinus (dark fibrils tend not to cover the cap in this way). However, in some collections of C.atrosquamosus the cap has expanded and the margin is olive brown and relatively smooth.

C.clandestinus in my experience has a lighter greenish-olive, tan or olive (paler) base color and scales or dark tufts appear more distinctly separated. The entire pileus of C.atrosquamosus has a scaly vs fibrillose appearance. Also, C.clandestinus may more often show a distinctly dark patch on the disc vs the diffuse spread of C.atrosquamosus. I typically collect C.clandestinus from spring through fall and it is known as a spring species in several regions. I have only collected C.atrosquamosus in the fall.

The type description also notes that in C.atrosquamosus the veil is white to yellowish brown (seen on stipe base) while in C.clandestinus the veil is yellow to greenish-yellow. This might appear as a more marked pale stipe base on C.atrosquamosus when young, and later, more patterned and brown than C.clandestinus. The paper also notes several microscopic differences that can be observed.

I will publish photographs of C.clandestinus separately to provide examples of sequenced collections for comparison. Frankly, it’s going to take us a while to get confident with these – and I find the specimens of C.atrosquamosus where scales do not cover the whole cap, hard to separate from C.clandestinus where fibrils may occur throughout the pileus.

Phylogeny

Source: Ammirati et al. 2021

Note: SDA491 is genetically identical to SDA357

Sequences

>SDA_357
AAGTAAAAGTCGTAACAAGGTTTCCGTAGGTGAACCTGCGGAAGGATCATTAATGAAAATAAACCTGATGAGTTGCTGCTGGTTCTCTAGGGAACATTGTGCACACTTGTCATTTTTATATCTCCACCTGTGCACCTTTTGTAGACCTGAATAATCCTGCAAGTCAGGTTGTGAGGAATTGACTTTCCTTACATTTTCAGGCCTATGTTTCTTCATATACTCCTTAATGTATGTTATAGAATGTAACAGGCCCTCTGTGCCTATAATCTATACAACTTTCAGCAACGGATCTCTTGGCTCTCGCATCGATGAAGAACGCAGCGAAATGCGATAAGTAATGTGAATTGCAGAATTCAGTGAATCATCGAATCTTTGAACGCACCTTGCGCTCCTTGGTATTCCGAGGAGCATGCCTGTTTGAGTGTCATTAATATATCAACCTCTTTAGCTTTTGCTTGTTGAGTGTTGGATGTGGGGGTGTTTTTGCTGGCCTTTTGAGGTCAGCTCCCCTGAAATGCATTAGCGGAACAAATTTGCTGACTCTGTTCATTGGTGTGATAACTATCTACGCTATTGACGGGGTGAAAGCAGAGTTCAGCTCCTAATAGTCCATTGACTTGGACAACTTTTTCATTTAATGTGACCTCAAATCAGGTAGGACTACCCGCTGAACTTAAGCATATCAATAAGCGGAGGAAAAGAAACTAACAAGGATTCCCCTAGTAACTGCGAGTGAAGCGGGAAAAGCTCAAATTTAAAATCTGGCAGTCTTTGGCTGTCCGAGTTGTAATCTAGAGAAGTGCTATCCGCGCTGGACG

>SDA_421
AAGTAAAAGTCGTAACAAGGTTTCCGTAGGTGAACCTGCGGAAGGATCATTAATGAAAATAAACCTGATGAGTTGCTGCTGGTTCTCTAGGGAACATTGTGCACACTTGTCATTTTTATATCTCCACCTGTGCACCTTTTGTAGACCTGAATAATCCTGCAAGTCAGGTTGTGAGGAATTGACTTTCCTTACATTTTCAGGCCTATGTTTCTTCATATACTCCTTAATGTATGTCATAGAATGTAACAGGCCCTCTGTGCCTATAATCTATACAACTTTCAGCAACGGATCTCTTGGCTCTCGCATCGATGAAGAACGCAGCGAAATGCGATAAGTAATGTGAATTGCAGAATTCAGTGAATCATCGAATCTTTGAACGCACCTTGCGCTCCTTGGTATTCCGAGGAGCATGCCTGTTTGAGTGTCATTAATATATCAACCTCTTTAGCTTTTGCTTGTTGAGTGTTGGATGTGGGGGTGTTTTTGCTGGCCTTTTGAGGTCAGCTCCCCTGAAATGCATTAGCGGAACAAATTTGCTGACTCTGTTCATTGGTGTGATAACTATCTACGCTATTGATGGGGTGAAAGCAGAGTTCAGCTCCTAACAGTCCATTGACTTGGACAACTTTTTCATTTAATGTGACCTCAAATCAGGTAGGACTACCCGCTGAACTTAAGCATATCAATAAGCGGAGGAAAAGAAACTAACAAGGATTCCCCTAGTAACTGCGAGTGAAGCGGGAAAAGCTCAAATTTAAAATCTGGCAGTCTTTGGCTGTCCGAGTTGTAATCTAGAGAAGTGCTATCCGCGCTGGACG

>SDA491 Cortinarius aff atrosquamosus
AGGAAGTAAAAGTCGTAACAAGGTTTCCGTAGGTGAACCTGCGGAAGGATCATTAATGAAAATAAACCTGATGAGTTGCTGCTGGTTCTCTAGGGAACATTGTGCACACTTGTCATTTTTATATCTCCACCTGTGCACCTTTTGTAGACCTGAATAATCCTGCAAGTCAGGTTGTGAGGAATTGACTTTCCTTACATTTTCAGGCCTATGTTTCTTCATATACTCCTTAATGTATGTTATAGAATGTAACAGGCCCTCTGTGCCTATAATCTATACAACTTTCAGCAACGGATCTCTTGGCTCTCGCATCGATGAAGAACGCAGCGAAATGCGATAAGTAATGTGAATTGCAGAATTCAGTGAATCATCGAATCTTTGAACGCACCTTGCGCTCCTTGGTATTCCGAGGAGCATGCCTGTTTGAGTGTCATTAATATATCAACCTCTTTAGCTTTTGCTTGTTGAGTGTTGGATGTGGGGGTGTTTTTGCTGGCCTTTTGAGGTCAGCTCCCCTGAAATGCATTAGCGGAACAAATTTGCTGACTCTGTTCATTGGTGTGATAACTATCTACGCTATTGACGGGGTGAAAGCAGAGTTCAGCTCCTAATAGTCCATTGACTTGGACAACTTTTTCATTTAATGTGACCTCAAATCAGGTAGGACTACCCGCTGAACTTAAGCATATC

>NAMA 2014 Ref 3954555
GTAAAAGTCGTAACAAGGTTTCCGTAGGTGAACCTGCGGAAGGATCATTAATGAAAATAAACCTGATGAGTTGCTGCTGGTTCTCTAGGGAACATTGTGCACACTTGTCATTTTTATATCTCCACCTGTGCACCTTTTGTAGACCTGAATAATCCTGCAAGTCAGGTTGTGAGGAATTGACTTTCCTTACATTTTCAGGCCTATGTTTCTTCATATACTCCTTAATGTATGTTATAGAATGTAACAGGCCCTCTGTGCCTATAATCTATACAACTTTCAGCAACGGATCTCTTGGCTCTCGCATCGATGAAGAACGCAGCGAAATGCGATAAGTAATGTGAATTGCAGAATTCAGTGAATCATCGAATCTTTGAACGCACCTTGCGCTCCTTGGTATTCCGAGGAGCATGCCTGTTTGAGTGTCATTAATATATCAACCTCTTTAGCTTTTGCTTGTTGAGTGTTGGATGTGGGGGTGTTTTTGCTGGCCTTTTGAGGTCAGCTCCCCTGAAATGCATTAGCGGAACAAATTTGCTGACTCTGTTCATTGGTGTGATAACTATCTACGCTATTGACGGGGTGAAAGCAGAGTTCAGCTCCTAATAGTCCATTGACTTGGACAACTTTTTCATTTAATGTGACCTCAAATCAGGTAGGACTACCCGCTGAACTTAAG

References

J Ammirati et al. 2020 “Cortinarius Subgenus Leprocybe, Unexpected Diversity and Significant Differences in Species Compositions between Western and Eastern North America” 46: 24.