Cortinarius vesterholtii Frøslev & T. S. Jeppesen, 2006

Frøslev, Tobias G., Jeppesen, Thomas S. & Laessøe, Thomas, 2006, Seven new calochroid and fulvoid species of Cortinarius, Mycological Research 110, pp. 1046-1058 : 1055

publication ID

https://doi.org/ 10.1016/j.mycres.2006.05.012

persistent identifier

https://treatment.plazi.org/id/0393543E-7A54-4A7D-FF72-FDDAD98AF970

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Plazi

scientific name

Cortinarius vesterholtii Frøslev & T. S. Jeppesen
status

sp. nov.

Cortinarius vesterholtii Frøslev & T. S. Jeppesen View in CoL , sp. nov.

MycoBank no.: MB 500733

( Figs 1G View Fig 1 , 2G View Fig 2 , 3C View Fig 3 & 4F View Fig 4 )

Etym.: vesterholtii (Latin), after Jan Vesterholt.

Pileo 50–80 mm lato, hemisphaerico,dein plano-convexo,glutinoso, primo brunneo, margine luteo-brunneo, KOH ope brunneo. Velo universale pallido vel violaceo. Lamellis pallide violaceis. Stipite 35– 55 X 10–15 mm, bulboso, bulbo marginato, violaceo, interdum margine bulbi e velo violaceo. Facie externa mycelioque KOH ope nullo. Carne albida,in apice stipitis violacea, sapore miti, odore nullo,KOH ope nullo vel pallido rosea. Sporis amygdaliformibus vel limoniformibus, grosse verrucosis, 10–11 X 6.5 µm.

Typus: Denmark: Østjylland: Århusskovene , Jens Baeks Vedkast , under Fagus sylvatica, 30 Sep. 1997, T. S. Jeppesen & T. G. FrØslev, TT1997-009 ( C - holotypus).

Pileus 50–80 mm, hemispherical then plano-convex, glabrous, glutinous, uniformly pale to darker brown (̿ 4B5 to 4C7–6D6), margin paler cream–brown to yellow–brown, sometimes with pale to violaceous universal veil remnants especially on margin. Lamellae emarginate,pale violaceous (15–17A2 to paler).Stipe 35– 55 X 10–15 mm with an often not so wide bulb (– 25 mm), often intensely violaceous (17–18A3–19A4), but often paler (̿ 17A2). The colour is very consistent and persistent, though it fades from below with age and often discolours brownish. Bulb often sharply marginate,though not so wide, bulbipellis and mycelial strands whitish, bulb margin on younger specimens sometimes with remnants of violaceous veil.Cortina violaceous.Veil pale to faintly violaceus. Context whitish, in stipe cortex violaceous. Taste mild, smell indistinct. Spores amygdaliform to citriform with broad long apex, with distinct coarse ornament, relatively dark in the microscope, 10–11 X 5.5–6.5 µm, average 10.4 ± 0.4 X 6.1 ± 0.3 µm; Q ¼ 1.72 ± 0.08.

Chemical reactions: KOH on pileipellis almost negative to brownish (6F7) but not red, on bulbipellis negative, in context negative or weak rose.

Habitat: Known from frondose forests with Fagus and Quercus on calcareous to mineral rich soil, but has also been found in mixed forests with Carpinus betulus, Q. petraea, Q. cerris and Tilia tomentosa.

Observations/Discussion: Among calochroid taxa, C. vesterholtii is easily recognised by the brown pileus colours, the violet stipe, and the negative alkaline reaction on the bulbipellis. Similar species have lighter or livelier colours on the pileus, and/or a pink alkaline reaction on the bulbipellis. The most obvious possibility of misidentification is discoloured specimens of C. sodagnitus and possibly C. parasuaveolens , both having positive alkaline reactions. Furthermore, C. vesterholtii has some morphological affinities to distantly related non-calochroid species such as C. purpurascens , which differ by the typical purple staining reaction of species in that group. Superficial resemblance with brownish stained specimens belonging to the C. coerulescens group is also a possibility. These, however, have spores without a net-like ornamentation, and have a well-differentiated hypodermal layer, not seen in any calochroid taxa, and pronounced innate fibrils in the pileus. Furthermore, the violaceous colours of the stipe and lamellae of these species are more bluish than in C. vesterholtii . The species has been treated under the name C. provencalis (e.g. Bidaud et al. 2001, Moser 1997). Moser’s concept of C. provencalis included (discoloured) collections of C. sodagnitus along with the present species. The collection published in Moser & Jülich (1985 –1999) as C. coeruleoochrascens almost certainly represents C. vesterholtii , a collection Moser referred to when describing C. provencalis ( Moser 1997) . The type of C. provencalis , however, represents a collection of C. sodagnitus (Frøslev et al., unpublished) leaving C. provencalis a synonym of C. sodagnitus . This also explains the larger variability of alkaline reactions and some morphological characters in the protologue of C. provencalis compared with the variability observed in C. sodagnitus and C. vesterholtii , respectively. The species is named after the Danish mycologist, Jan Vesterholt, who urged us to continue our study of this interesting group of Cortinarius . We have seen several photographs and references to this species (as C. provencalis ) from the Mediterranean area, and it is most likely widespread, but not common in this area, whereas the species seems to be very rare in Northern Europe. An ITS sequence from the holotype of C. vesterholtii is available at GenBank (accession DQ350842 View Materials ).

Additional specimens examined: Denmark: MØn: Møns Klinteskov , in Fagus forest on calcareous soil, 8 Sep. 1999, P. B. Hansen & J. Vesterholt, TSJ1999-039 ; Østjylland: Århusskovene, Jens Baeks Vedkast , Fagus forest on mineral rich soil, 5 Oct. 1997, T.S.J., TT1997-014; loc. cit., 7 Oct. 2003, T.S.J., TSJ2003-101 ; loc. cit., 3 Oct. 2004, T.S.J., TSJ2004-064 . ̅ Hungary: Somogy: Bels o-Som-} ogy, Böhönye, in mixed forest with Carpinus betulus, Quercus petraea, Q. cerris and Tilia tomentosa, 9 Oct. 2004, B. Dima, DB1362 (hb. Dima). ̅ Italy: Sardegna: Olbia, Q. ilex on somewhat siliceous soil, 1 Nov. 2004, T.G.F. & T.S.J., TF2004-101 ; loc. Cit. , TF2004-102 .

Kingdom

Fungi

Phylum

Basidiomycota

Class

Agaricomycetes

Order

Agaricales

Family

Cortinariaceae

Genus

Cortinarius

Section

Phlegmacium

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