Types: UNITED STATES: California: Jasper Ridge, near Stanford University (approx. 37.4061°N, 122.2446°W, alt. approx. 150 m a.s.l.) under Quercus sp., 11 Jan. 1912, J.I.W. McMurphy (126), det: W.A. Murrill (Holotype. herbarium acc. no. NY 814866, HJB1000279; Isotype. herbarium acc. no. WTU-F-039669, HJB1000354).

Diagnosis: Pileus large, thick, convex to nearly plane, not umbonate, 8-10 cm. broad; surface glabrous, viscid, cream-colored to light-buff, margin entire, incurved, pallid; context white, with farinaceous odor and taste; lamellae sinuate, rather narrow, plane or arcuate, crowded, yellowish to subfulvous, entire and concolorous on the edges; spores ovoid, finely punctate, melleous under the microscope, fulvous in mass, 10-12 X 7 μ; stipe enlarged below, thick, fleshy, solid, white within and without, smooth, decorated with the remains of the fibrillose, evanescent veil, 6-8 cm. long, 2-3 cm. thick.

Commentary: A herbarium note written by L.R. Hesler in 1972 appears to confirm what he wrote in his unpublished North American species of Hebeloma in 1977, that he believed this to be an unusual Hebeloma without cheilocystidia or clamp connections. Smith et al. (1983) also published a description of this species as a Hebeloma. A second herbarium note includes a rough sketch of the mushroom together with a rusty brown spore print. Our analysis revealed weakly ornamented, amygdaloid spores (10–12 × 6–7.5 µm) and the absence of cheilocystidia and clamp connections. The morphology suggests this is most likely a Cortinarius s.l. species, which is confirmed by an ITS sequence which was generated from the holotype. This sequence suggests that P. farinaceum has a younger synonym, P. albofragrans, originally described from the US in Cortinarius (Moser and Ammirati 1997). The type sequence of P. albofragrans was published in the context of a type study (Liimatainen et al. 2014). The ITS fragment of the two types and three additional sequences from the US (KJ421165, KJ421166, Garnica et al. 2016; and MW488236, S.D. Adams 17 Jan 2021, unpublished) are identical; a Mexican sequence published under the name P. albofragrans (KT827316, H.R. Lopez 25 Sep 2015, unpublished), has issues, whether or not the identification is correct is indeterminable from the data. The corresponding UNITE species hypotheses (3%) is SH1141595.08FU. All sequences included are from the US. The most similar ITS sequences to the type sequences to P. farinaceum are at less than 92% similar, and were referred to P. pseudonaevosus, and P. patrickense by Liimatainen et al. (2014) (https://blast.ncbi.nlm.nih.gov/Blast.cgi, consulted 3 Jun 2022). The only phylogenetic study including P. albofragrans was published by Soop et al. (2019) who failed to resolve its infrageneric position (at the time the subgeneric position in C. subg. Phlegmacium), see Soop et al. (2019), Fig. 2 (continued); the depicted sister species relationship with P. serarium (as C. serarius) was unsupported. Based on BLAST results, including or excluding LSU data published for P. albofragrans, we have not been able to determine any supported phylogenetic relationship with any published sequence, thus we refer the reader to Soop et al. (2019). Soop et al. (2019) included the two species with the most similar ITS to P. farinaceum to the C. Sect. Phlegmacioides clade (P. pseuonaevosum) and the C. sect. Arguti clade (P. patrickense), presumably corresponding to P. sect. Phlegmacoidea and P. sect. Arguti of Liimatainen et al. (2022). Phlegmacium patrickense and P. pseudonaevosum are phylogenetically not closely related to each other. As these larger phylogenetic analyses could not resolve the phylogenetic or taxonomic position of P. albofragrans and thus P. farinaceum, we refrained from including an analysis here. The synonymy of P. albofragrans with P. farinaceum is, apart from ITS, also supported by the spore characters; both type collections stem from California and were collected under oak. The original description of P. albofragrans mentions that the smell is like that of C. percomis (P. percome; Soop et al. 2019 recognize the separate clade C. sect. Percomes in their phylogenetic reconstruction; P. sect. Percomia in the classification by Liimatainen et al. 2022). However, Moser and Ammirati (1997) also add “Odor … also of some flours”., fitting with the epithet selected by Murrill. We thus list P. albofragrans as synonym of P. farinaceum. It should be noted that P. farinaceum is nomenclaturally and taxonomically not the same as C. farinaceus (Murrill) Kauffman, originally described in Gymnopilus and now with the replacement name Agrocye dennisii Watling (Murrill 1915; Kauffman 1926; Watling 1977).