Pholiota "sp-IN01"
Pholiota "sp-IN01" is a species of fungi found across North America with observations on the West Coast, Rocky Mountains, and East Coast USA. They are currently documented in both the United States of America and Canada within North America. Collections appear to be concentrated in Eastern North America. As of April 22, 2025, there are 59 observations of Pholiota "sp-IN01" on iNaturalist with ITS data available [1] It grows May through December and peaks August through October. It is synonymous with Pholiota sp. 'IN01' [2]
Description[edit | edit source]
Caps yellow, yellow-orange, brownish-yellow, brownish-orange, or at times with reddish tones. The cap texture is most often presenting as scaley but sometimes appearing as fibrous scales more dense at the center of the cap. Described by user thefungiproject as "Cap scurfy with orange scales and inrolled margin." Cap size ranges from slightly less than 1 cm to 4cm wide as measured or pictured with a scale [3][4] [5] [6] [7] [8] [9] [10] [11] Margin sometimes appendiculate with yellow fibrous material. The cap can on occasion appear distinctly umbonate [12] Stems often thin and with yellow scales when fresh and a ring zone where the cap once met the stem while young. iNaturalist user thefungiproject describes stems as "Stipe also scurfy with orange scales (lesser than cap)." [13] One measurement of stem length and width of 2-4mm wide and 2.5-4.5cm long [14] Gills are pale yellow in color with a crenulate gill edge. Mycelium is pale yellowish to whitish. The odor is described as indistinct [15] , of anise [16] , pleasant [17] , or none [18] [19]. Taste is described as mildly bitter [20], bitter [21] [22] or very bitter [23]. KoH reaction is pictured as negative [24] but one user reports a positive reaction but has no photos [25]. User mandymushii has photos detailing a yellow UV reaction on the stem, gills, and cap with 365nm UV light [26] while user mitchellpittsley demonstrates a whitish UV reaction on the gills with 396nm UV light [27].
Spore print is brown. User heelsplitter measured spores and viewed other microscopic structures with Piximetre and found: "Clamp connections present in the pileipellis and in the lamellar trama. Basidia 2-sterigmate. Cheilocystidia capitate and yellow in NH4OH (chrysocystidia?). Pleurocystidia seemed to be absent. Spore measurements from Piximetre: (6.6) 7.1 – 8.9 (9.9) × (4) 4.3 – 5.3 (5.9) µm, Q = (1.5) 1.54 – 1.79 (1.8); N = 30, Me = 7.8 × 4.7 µm; Qe = 1.7 Individual spores: 7.88 × 5.23 µm, 7.32 × 4.35 µm, 7.39 × 4.85 µm, 6.95 × 4.45 µm, 7.25 × 4.23 µm, 6.56 × 4.42 µm, 7.22 × 4.44 µm, 8.80 × 4.83 µm, 8.48 × 5.16 µm, 7.46 × 4.46 µm, 7.39 × 4.49 µm, 7.36 × 4.61 µm, 7.91 × 4.37 µm, 7.55 × 4.50 µm, 9.09 × 5.34 µm, 7.93 × 4.62 µm, 7.30 × 4.26 µm, 7.45 × 4.61 µm, 7.25 × 4.41 µm, 8.92 × 5.17 µm, 7.81 × 4.36 µm, 7.38 × 4.79 µm, 7.13 × 4.16 µm, 7.99 × 4.33 µm, 9.04 × 5.38 µm, 8.00 × 4.67 µm, 7.30 × 4.44 µm, 6.65 × 4.02 µm, 8.82 × 5.45 µm, 9.93 × 5.86 µm" Three other observations featured microscopy but included no measurements [28] [29] [30]
Similar Species[edit | edit source]
Pleuroflammula multifolia : User pinonbistro writes "Compare to MN206909 Pf. multifolia, the reference sequence for the taxon chosen by Irja Saar of UNITE. Pf. subsulphurea sequences on GenBank appear to be mislabeled. It may be that the two are synonyms in which case Pf. multifolia is the older name.
An alignment of ITS sequences indicates that Pholiota "sp-IN01"=Pf. multifolia" [31]
Sequences of Pholiota "sp-IN01" are also at times labelled as Pholiota tuberculosa, Pleuroflammula tuberculosa, Pholiota subsulphurea, or Pleuroflammula subsulphurea on iNaturalist.
Taxonomy[edit | edit source]
Stephen Russell posted to the FaceBook group Fungal Sequencing Results on April 2 2025 at 9:38 PM that "Below is a very early draft of a synonymy map for a bunch of Pholiota types. It would be a good PhD project for someone. Have only compared it against local data to this point as NCBI BLAST is still running. This was a part of a methods trial using only the smallest portion of tissue from types. Overall it got fairly good recovery for the first pass. Haven't done any checking of dates/priority, so there is still a whole lot left to do." Within Stephen's list of preliminary results he notes that:
"Pholiota subsulphurea
=Pholiota "sp-IN01""
He goes on in the comments section to add that the "Main reason I post this is so people can see the species involved if it may impact any of their current or future work. This list is not meant to be a publication-ready or near-publication-ready list of results. Seqs will likely end up in Genbank, but unclear when as the institution holding the specimens will be the entity uploading." [32]
Ecology[edit | edit source]
Pholiota "sp-IN01" grows on wood and is assumed to be saprobic. Its hosts have been recorded as Hardwood [33] [34] [35] [36], Tulip Poplar [37], Sugar Maple [38], and Shagbark Hickory [39]. On the West Coast of North America it has been reported as "Near tan oak and Doug fir" [40] and "Near Doug fir/tan oak/bay laurel/maple/madrone/chinquapin/evergreen Huckleberry/salal" [41]