Pluteus rimosellus (Singer)

Del, Jonathan A. & Perry, Brian A., 2025, The genus Pluteus (Basidiomycota, Agaricales, Pluteaceae) from Tafea Province, Republic of Vanuatu, Phytotaxa 709 (1), pp. 1-104 : 62-70

Pluteus rimosellus (Singer) , Singer & Digillio, Liloa 25: 262, 1952 ( Figs. 31 , 32 , 33 )

Reported heterotypic synonyms:

= Pluteus subfibrillosus Singer, Transactions of the British Mycological Society 39: 187 (1956)

Probable heterotypic synonyms:

= Pluteus pallidosquamulosus E. Malysheva, V. Malysheva, A. Alexandrova, & O. Morozova, Phytotaxa 461.2: 85–86 (2020)

Diagnosis:— Pluteus rimosellus from Aneityum is characterized by a convex, slightly umbonate, marginally sulcate pileus with a grayish tan tomentose surface with patches exposing the off-white context and a venose-rugose or appressed squamulose disc composed of reddish brown pustules. The stipe is pale brown and minutely flocculose with a bulbous base. Microcharacters include broadly ellipsoid basidiospores with a mean size of 7.0 × 5.7 µm, fusoid-ventricose cheilocystidia and pleurocystidia both typically obtuse or infrequently with mucronate appendages, a euhymeniderm pileipellis with terminal elements comprised of pale brown pigmented, clavate-mucronate cells, sphaeropedunculate mucronate caulocystidia, and an absence of clamp connections.

Description:— Pileus 12–45 mm diam., convex to campanulate expanding to hemispherical in age with a moderate umbo, disc finely to coarsely venose-rugose, margin sulcate; surface dull, dry, veins composed of pustulessubtomentum radiating and diminishing towards margin, appressed-fibrillose elsewhere with rimulose patches exposing the underlying off-white to gray context; pustules/tomentum dark reddish brown (oac734–oac737) fading to pallid brown (oac771–oac773) in age and away from the disc, fibrils and surface pallid grayish tan (oac779–oac781 or oac800–oac802). Context up to 4 mm thick, off-white to pale gray. Lamellae free, close with 2 tiers of lamellulae, thin, margin turning serrate in age, white turning dull pink (oac767) in age. Stipe 20–48 × 3–5 mm, central, terete, cylindrical over a subbulbous to bulbous base, solid; surface dull, dry, glabrous or finely appressed-fibrillose to finely flocculose towards the apex, cream (oac794–oac795) to white with pale brown (oac771–oac773) fibrils and floccules, context white. Odor indistinct. Taste indistinct.

Basidiospores 5–8 (–9) × 5–8 µm [x mr = 6.64–7.0 × 5.37–6.2 µm, x mm = 7.02 ± 0.29 × 5.73 ± 0.42 µm, Q = 1–1.6, Q mr = 1.21–1.25, Q mm = 1.23 ± 0.02, n = 50, s = 3], subglobose to broadly ellipsoid, smooth, hyaline, with a guttule, inamyloid, thick-walled. Basidia 20–30 (–36) × 7–9 µm, clavate, 4-spored, hyaline, guttulate, thin-walled, sterigmata 2–4 × 0.5–2 µm. Basidioles 13–28 × 7–12 µm, clavate, hyaline, guttulate, thin-walled. Lamellar edge heterogenous. Cheilocystidia 38–78 (–92) × 14–28 (–40) µm, in fascicles or forming a well-developed strip on the lamellar edge, versiform, clavate to broadly clavate, fusoid-ventricose, or seldom sphaeropedunculate, obtuse or in some collections mucronate with an appendage (up to 10 µm long) or digitate-capitate with 1–2 appendages or nodules, rarely with apical incrustations, hyaline, thin-walled. Pleurocystidia (38–) 53–72 (–86) × (10–) 16–30 (–38) µm, scattered to abundant, fusoid-ventricose to lageniform, obtuse or in some collections frequently mucronate with an appendage or digitate-capitate with 1–2 appendages/nodules, rarely with apical incrustations, hyaline, thin-walled. Pileipellis an intricate trichoderm to euhymeniderm over a cutis subpellis, composed of terminal elements 56–92 (–115) × 14–26 µm, in erect to suberect fascicles, narrowly to broadly clavate or narrowly lageniform, obtuse, in some collections occasionally mucronate with an appendage (up to 17 µm long) or capitate with 1–2 nodules, with pale brown plasmatic pigment or hyaline, non-incrusted, non-gelatinous, thin or apically thick-walled (in one collection); subpellis a cutis, composed of hyaline or some with pale brown plasmatic pigment, non-incrusted, non-gelatinous, thin-walled hyphae, 3–12 µm diam.. Pileus trama composed of interwoven, hyaline, non-gelatinous, thin-walled, clavate to inflated hyphae, 3–24 µm diam.. Lamellar trama inverse, composed of hyaline, non-gelatinous, thin-walled hyphae, 3–20 µm diam.. Stipitipellis a cutis, composed of hyaline or sometimes with pale brown plasmatic pigment, non-incrusted, non-gelatinous, thin-walled hyphae, 3–16 µm diam.. Caulocystidia 34–60 (–73) × 8–19 (–38) µm, scattered in fascicles, clavate to sphaeropedunculate, obtuse, in some collections frequently mucronate with an appendage (up to 22 µm long) or capitate with 1–2 nodules, hyaline or sometimes with pale brown plasmatic pigment, thin-walled. Clamp connections absent in all tissues examined.

Habitat and known distribution:—Solitary to gregarious on decayed wood in subtropical montane primary broadleaf- Araucariaceae / Podocarpaceae rainforest with Agathis macrophylla ( Araucariaceae ), Balanops pedicellata ( Balanopaceae ), Calophyllum neoebudicum ( Calophyllaceae ), Dendrocnide latifolia ( Urticaceae ), Ficus septica ( Moraceae ), Ficus smithii ( Moraceae ), Garcinia platyphylla ( Clusiaceae ), Geissois denhamii ( Cunoniaceae ), Hernandia moerenhoutiana ( Hernandiaceae ), Macaranga dioica ( Euphorbiaceae ), Podocarpus vanuatuensis ( Podocarpaceae ), Polyscias cissondendron ( Araliaceae ), and Syzygium spp . ( Myrtaceae ), Vanuatu (Aneityum). Also known from Argentina, Brazil, Vietnam.

Material examined:— VANUATU. Tafea Province: Aneityum, trail through Antowojon area , 20°13.142′S, 169°47.788′E, elev. 119 m, 28 July 2017, coll. J. A del Rosario & B. A . Perry, JAD 11 ( HAY); Aneityum, Noposjec , 20°12.710′S, 169°46.990′E, elev. 192 m, 11 December 2019, coll. J. A . del Rosario , JAD 338 / 338 B ( HAY); Aneityum, Noposjec , 20°12.420′S, 169°46.795′E, elev. 184 m, 11 December 2019, coll. J. A . del Rosario , JAD 343 ( HAY) .

Notes:— Pluteus rimosellus was originally described by Singer from Argentina ( Singer& Digilio 1952) and recently an isotype was re-examined and accompanied with a modern Brazilian collection ( Menolli et al. 2015a). Unfortunately, a recent re-examination of a paratype by Rodríguez (2024) found the specimen to be in poor condition and only spores were observable. Singer (1956) commented that P. fibrillosus Murrill (1917: 134) , had a close relationship with both P. rimosellus and P. subfibrillosus Singer (1956: 187) , but did not clarify how to distinguish between these taxa. Pluteus fibrillosus was described from Louisiana by Murrill (1917) and since then the holotype since then has been examined by multiple authors ( Banerjee & Sundberg 1993, Menolli et al. 2015a, Singer 1956, Smith & Stuntz 1958). The observations of Menolli et al. (2015a) are consistent with previous examinations, including distinct incrustations in the pileipellis, but the same accounts were unable to confirm Singer’s observations of pigmented cystidia. Despite Singer’s observed similarities in P. fibrillosus to P. rimosellus and P. subfibrillosus, Menolli et al. treated P. fibrillosus as a separate species. In addition, Menolli et al. compared an isotype of P. rimosellus plus additional Brazilian material against the holotype of P. subfibrillosus , and due to similar micromorphology concluded that P. subfibrillosus should be considered a synonym of P. rimosellus .

Extensive comparison of the protologues of both P. rimosellus and P. subfibrillosus reveals a wide range of macrocharacters that are also present and varied between the Vanuatu specimens. Specimens JAD 338 and JAD 338-B were initially collected on the same piece of rotten wood; however, it was uncertain at the time if they were the same species. JAD 338-B was composed of less mature and more venose fruiting bodies while JAD 338 had more mature, slightly paler basidiomes with one venose and a smaller one not ( Fig. 31 ). Micromorphological comparison confirmed JAD 338-B as being a less mature form of JAD 338. These more venose forms of the Vanuatu specimens place them closer to the descriptions of P. subfibrillosus ( Singer 1956, 1958). The other Vanuatu specimens of this taxon, JAD 11 and JAD 343, have a pileus disc that is more appressed-squamulose to subtomentose ( Fig. 32 ), and much more similar to P. rimosellus , which has not been described as venose ( Singer 1958, Singer & Digilio 1952). Overall, consistent macrocharacters for this species would include the pileus with a sulcate margin, a grayish tan appressed-fibrillose rimulose surface with a disc being either squamulose to rugose-venose comprised of reddish brown subtomentum, and a white stipe covered with pale brown minute floccules. This would strengthen the case for Menolli et al. synonymizing P. subfibrillosus under P. rimosellus ( Menolli et al. 2015a) . Based on both type descriptions of P. rimosellus and P. subfibrillosus plus the re-examinations by Menolli et al. (2015a), the specimens from Vanuatu fit closer to the concept of P. rimosellus with some discrepancies. None of the Vanuatu material has pigmented pleurocystidia observed by previous authors. Both the cheilocystidia and pleurocystidia are slightly longer compared to the type collections being closer in size to the Brazilian collection made by Menolli et al. (2015a), but this slightly varies between specimens. Otherwise, the size and shape of the globose to ellipsoid spores and the pileipellis elements fit well based on all other accounts, despite caulocystidia not being reported as in this material. The disc variation being either a reduced squamulose to a developed rugose-venose and the variously ornamented cystidia between specimens clearly point to a species with broad morphological variation.

Comparisons among the Vanuatu specimens reveal minor differences in micromorphology regarding cystidia apical ornamentation, although these traits are not predominant among cell types. For example, the well matured basidiomes in JAD 338 had some pleurocystidia that were infrequently observed with mucronate-digitate apices, while the less matured basidiomes in collection JAD 338-B occasionally has similar ornamentation on the cheilocystidia, and both share this on a minority of the pileipellis terminal cell apices. This particular trait would suggest comparison to P. jaffueli (Spegazzini) Singer (1954: 123) from Chile and Argentina, but this species differs primarily in having marginate lamellae and significantly larger pileipellis elements (66–150 × 13.8–30.8 µm) ( Horak 1964, Singer 1954, 1956, 1958). In addition, a type of incrustation was sometimes observed on the cheilocystidia in JAD 338 and on the pleurocystidia of JAD 338-B. Even the caulocystidia of JAD 338 had a higher degree of apical variation compared to the other collections. With regards to JAD 11 and JAD 343, none of these traits were observed, except the pileipellis elements of JAD 343 were infrequently observed with apically thickened walls. While these characteristics may not be considered consistent enough to be taxonomically informative it is still worth noting and does suggest a high level of micromorphological variation within this species. Despite this minor variation, these collections can be united through ITS molecular data and tentatively identified to P. rimosellus in combination with matching physical characters from the type descriptions and matching the overall shape and size range of the spores, cheilocystidia, pleurocystidia, and pileipellis arrangement and elements.

In the phylogenetic analysis of ITS data ( Fig. 15b ) a recently described Vietnamese species, P. pallidosquamulosus E.F. Malysheva & A.V Alexandrova (2020: 85) , falls within the strongly supported branch with the Vanuatu specimens of P. rimosellus and the Brazilian P. cf. fernandezianus specimen. The study did not include ITS data for the Brazilian specimen nor was it mentioned or noted in the protologue ( Malysheva et al. 2020). Pairwise analysis of overlapping ITS regions shows that the sequence for P. pallidosquamulosus ranges from 97.18–97.83 % similarity to the Vanuatu specimens, and 97.06–99.05 % similarity to the Brazilian sequence. As mentioned in the commentary of the Aneityum material identified as P. fernandezianus, Menolli et al. (2015c) had revised collection “RSPF330”, initially identified as P. beniensis , to P. cf. fernandezianus due to an absence of macromorphological data. Microscopic comparison between the Vanuatu material and the observations provided by Menolli et al. (2015c) match up well, however their material contained slightly longer pleurocystidia and pigmented pleurocystidia and cheilocystidia. Despite the absence of macromorphological data in “RSPF330”, similarity in micromorphology combined with ITS ( JQ065028 ) molecular data analysis places it with the Vanuatu specimens on a well-supported branch and suggests the identity of P. rimosellus . The micromorphology of P. pallidosquamulosus compared to the Vanuatu collections is practically a perfect match, with a minor exception of having slightly narrower pleurocystidia. Pluteus pallidosquamulosus even shares the minor variation seen throughout all the Vanuatu specimens, such as some pileipellis cells being slightly thick-walled, some cheilocystidia being apically papillate, or some pleurocystidia being subcapitate. The photo provided in the description bears a strong likeness to the Vanuatu specimens JAD 11 and JAD 343 suggesting similarity to P. rimosellus , and is dissimilar from the rugose-venose forms of the other collections and P. subfibrillosus ( Figure 4A , Malysheva et al. 2020). Comparing the type description of P. pallidosquamulosus to the type descriptions and re-examinations of P. rimosellus and P. subfibrillosus suggests they are the same species due to high morphological similarities ( Menolli et al. 2015a, Singer 1956, 1958, Singer & Digilio 1952). Therefore, it is unlikely P. pallidosquamulosus should be treated as a new species and may be better identified as P. rimosellus . Unfortunately, ITS data is unavailable for any of the types or additional collections of P. rimosellus or P. subfibrillosus , and this would be particularly useful in unifying these collections. However, this extensive literature comparison can confidently conclude this identity, and determines P. rimosellus as a morphologically variable species.

Pluteus aff. semibulbosus (Lasch) Gillet, Les Hymenomycetes ou Description de tous les Champignons qui croissent en France: 395 (1876) ( Figs. 34 , 35 )

≡ Agaricus semibulbosus Lasch ex Fr., Epicrisis Systematis Mycologici : 140 (1838)

Diagnosis:— Pluteus aff. semibulbosus from Tanna is characterized by a hygrophanous, pale pink to off-white glabrous, pellucid-striate pileus and a white stipe with a subbulbous base arising from a white tomentum. Microcharacters include subglobose basidiospores (8.0 × 7.1 µm), versiform cheilocystidia being broadly clavate to fusoid-ventricose, fusiform pleurocystidia, a euhymeniderm pileipellis consisting of clavate cells, clavate caulocystidia, and an absence of clamp connections.

Description:— Pileus 20–34 mm diam., convex expanding to hemispherical in age with or without a slight central depression, sulcate up to half-way from margin, disc rugulose or smooth; surface dull at the disc when dry becoming pellucid-striate when moist, hygrophanous, dry to moist, glabrous when moist, to minutely appressed-fibrillose/subtomentose when dry; surface overall pale to dull pink (oac669/oac597–oac599) typically turning white from the disc outwards in age or when drying, or white overall. Context 1–3 mm thick, white. Lamellae free, subdistant with 2–3 tiers of lamellulae, thin (1–1.5 mm thick), pale pink (oac667–oac669). Stipe 25–30 × 3–4 mm, central, terete, cylindrical with a subbulbous base arising from a white tomentum, solid; surface shiny, dry, longitudinally fibrous, white to off-white, context white. Odor indistinct. Taste indistinct.

Basidiospores 7–9 (–10) × 6–9 µm [x mr = 7.84–8.14 × 7.06 µm, x mm = 7.99 ± 0.21 × 7.06 ± 0.02 µm, Q = 1–1.33, Q mr = 1.11–1.15, Q mm = 1.13 ± 0.01, n = 50, s = 2], globose to subglobose or rarely broadly ellipsoid, smooth, hyaline, with a guttule, inamyloid, thick-walled. Basidia 19–30 × 6–12 µm, clavate to broadly clavate, 4-spored, hyaline, guttulate, thin-walled, sterigmata 2–4 × 0.5–1 µm. Basidioles 18–26 × 7–10 µm, clavate, guttulate, hyaline, thin-walled. Lamellar edge sterile. Cheilocystidia 36–80 × 15–28 µm, versiform, clavate to broadly clavate, fusoid-ventricose to narrowly lageniform, obtuse or short to long capitate, hyaline, thin-walled. Pleurocystidia 47–103 × 14–41 µm, fusiform to fusoid-ventricose, or narrowly lageniform to broadly utriform, obtuse or sometimes truncate, sometimes basally septate, hyaline, thin-walled. Pileipellis a euhymeniderm, composed of a majority of cells 25– 110 × 6–28 µm, cylindro-clavate to broadly clavate or rarely fusoid-ventricose, obtuse, hyaline, non-incrusted, non-gelatinous, thin-walled. Pileus trama interwoven, composed of hyaline, non-gelatinous, thin-walled, clavate to inflated hyphae, 3–22 µm diam.. Lamellar trama inverse, composed of hyaline, non-gelatinous, thin-walled hyphae, 3–19 µm diam.. Stipitipellis a cutis, composed of hyaline, non-incrusted, non-gelatinous, thin-walled hyphae, 3–14 µm diam., commonly with excrescences. Caulocystidia 20–60 × 6–18 µm, scattered to clustered, cylindro-clavate to clavate, obtuse or rarely capitate, sometimes with basal septae, hyaline, thin-walled. Clamp connections absent in all tissues examined.

Habitat and known distribution:—Gregarious on decayed wood in subtropical lowland mixed-use agro tree garden and secondary broadleaf rainforest containing Bischofia javanica ( Phyllanthaceae ), Burckella obovata ( Sapotaceae ), Claoxylon gillisonii ( Euphorbiaceae ), Dendrocnide latifolia ( Urticaceae ), Didymocheton spp . ( Meliaceae ), Ficus spp . ( Moraceae ), Garcinia pseudoguttifera ( Clusiaceae ), Homolanthus nutans ( Euphorbiaceae ), Macaranga dioica ( Euphorbiaceae ), and Syzygium nomoa ( Myrtaceae ) and lowland-montane secondary broadleaf- Podocarpaceae rainforest containing Balanops pedicellata ( Balanopaceae ), Calophyllum neoebudicum ( Calophyllaceae ), Cryptocarya wilsonii ( Lauraceae ), Ficus wassa ( Moraceae ), Ixora aneityensis ( Rubiaceae ), Podocarpus vanuatuensis ( Podocarpaceae ), and Syzygium spp . ( Myrtaceae ), Vanuatu (Tanna).

Materials examined:— VANUATU. Tafea Province: Tanna, base of Mt. Kuning , 19°37.602′S, 169°25.870′E, elev. 286 m, 30 August 2018, coll. J. A . del Rosario, JAD 166 ( HAY); Tanna, along banks of Numdretum River , 19°37.482′S, 169°25.928′E, elev. 267 m, 5 December 2018, coll. J. A . del Rosario , JAD 197 ( HAY) .

Notes:—There has been disagreement among multiple authors about the species concept of P. semibulbosus , as some have described the pileipellis to consist of subglobose elements ( Lange 1936, Orton 1960, 1986), while others recognize this taxon and others as conspecific within the P. plautus (Weinmann) Gillet (1876: 394) species complex ( Vellinga 1990, Vellinga & Schreurs 1985). The original circumscription “pileo carnosulo hemisphaerico obtuso atomoto-molli sulcato…” ( Fries 1838) was interpreted by Vellinga and Schreurs (1985) and Ferisin and Dovana (2019) to represent a species with a pileus cuticle comprised of particles, which when viewed microscopically is a trichodermal pileipellis containing elongated elements typical for sect. Hispidoderma . Both Vanuatu specimens fit this description, but their appearance slightly varies based on environmental conditions during collection. JAD 166 contains one basidiome with a pure white pileus and the other is an overall pinkish brown. The pilei of both collections are pellucid-striate, glabrous to minutely fibrillose/subtomentose and slightly rugulose at the disc ( Fig. 34 ). JAD 197 had drier basidiomes, being a similarly colored pinkish brown around the pileus margin while the center is off-white and minutely fibrillose. Both specimens contain a pileipellis composed of elongated clavate terminal elements. The stipe of P. semibulbosus was originally described as “…subtiliter fistuloso pubescente, basi bullato” ( Fries 1838), which could be interpreted as being fibrillose/pubescent with a bulbous base and a match to both Vanuatu specimens.

Phylogenetic analysis by Justo et al. ( Justo et al. 2011b) determined the broad morphological concept of P. plautus by Vellinga and Schreurs (1985) comprising multiple species did not include P. semibulbosus , and concluded this taxon is a separate species requiring wider sampling for molecular and morphological distinction. For this study’s phylogenetic analysis of ITS data ( Fig. 15a ), the two Vanuatu collections are positioned in a strongly supported clade representing sequences of P. semibulbosus (BS 95 %, PP 1.0) with low to moderately supported internal topology. The two Vanuatu specimens fall within a well-supported lineage (BS 98 %, PP 1.0) with a Japanese collection identified as P. aff. semibulbosus ( HM562090 ), a Spanish collection of P. cf. semibulbosus ( KR022020 ), a Slovenian ( MK534552 ), Vietnamese (OQ732740), and two Italian ( MK446329 , MK446328 ) specimens identified as P. semibulbosus . Pairwise analysis of overlapping ITS regions of the two Vanuatu specimens compared to these sequences indicates a range of 99.11–99.82 % similarity to the previously mentioned taxa. Unfortunately, morphological data for the Japanese and Spanish collections is unavailable for comparison. Compared to the Italian/Slovenian collections, the Vanuatu specimens are distinguished macroscopically by having a pinkish brown pileus rather than white with a pale brown disc, and microscopically through larger spores, pleurocystidia and cheilocystidia, and more variable cheilocystidia with tapered to capitate apices ( Ferisin & Dovana 2019). Compared to the Vietnamese material, the overall morphological descriptions fit quite well with each other ( Malysheva et al. 2023). Phylogenetically, this lineage may be considered a separate species, but it is worth extensively comparing the Vanuatu specimens to the better-defined descriptions determined to be P. semibulbosus from South Korea ( Park et al. 2017) and Turkey ( Kaygusuz et al. 2019), which are placed in the adjacent lineages. Overall, the Vanuatu specimens’ microcharacters are also distinct in significantly larger spores, pleurocystidia and cheilocystidia compared to the South Korean and Turkish accounts. The versiform-shaped cheilocystidia of the Vanuatu specimens are closer to those in the Turkish material, while the others seem less variable and overall clavate. Pairwise analysis of the Vanuatu specimens to sequences of P. semibulbosus representative of the other two lineages shows 98.76–98.93 % similarity to those from Turkey ( MK123344 , MK123344 ) and 98.05– 98.23 % similarity to those from South Korea ( KF668315 , MF437007 ). A separate Vanuatu collection made in Aneityum, collection JAD 346 as P. cf. haywardii (discussed above), is placed in a basal clade with the two South Korean collections. Between the Vanuatu collections of P. aff. semibulbosus and P. cf. haywardii , the main superficial differences are that the Vanuatu P. cf. haywardii has a white cap with tan streaks and a cream stipe. Microscopic differences include P. aff. semibulbosus having larger spores, larger pleurocystidia, and larger more versiform and lageniform cheilocystidia. Pairwise analysis of overlapping ITS data shows that the sequence from P. cf. haywardii is 97.7–97.90 % similar to the Vanuatu collections of P. aff. semibulbosus (JAD 166 and JAD 197). Because of these features combined with molecular evidence it is preferred to maintain them as separate units until wider sampling and in-depth study can better define species limits. Undoubtedly, there is some overlap between the specimens and the size range of the microcharacters in the Vanuatu specimens is likely of taxonomic importance. Further studies including a new type designation, intensive re-examination of existing specimens, and additional molecular data are necessary in order to clearly delimit P. semibulbosus and others within this broad complex. For now, the Vanuatu specimens will be treated as P. aff. semibulbosus .

Figures

FIGURE 4. Basidiome of Pluteus petasatus in situ (JAD 298). Scale bar = 10 mm. Photo by: Brian Perry.

FIGURE 15a–c. Maximum Likelihood phylogeny of sect. Hispidoderma based on ITS sequence data (-lnL = 7783.640376). Sequences of specimens from Vanuatu are indicated in bold type. Stars indicate type specimens. Values separated by / refer to ML bootstrap proportions and Bayesian posterior probabilities, respectively. Only values greater than 70/0.70 are shown. Nodes receiving support values greater than 90/0.95 are highlighted in bold.

FIGURE 31. Basidiomes of Pluteus rimosellus. a. Immature basidiomes of Pluteus rimosellus (JAD 338-B). b. Mature basidiomes of Pluteus rimosellus (JAD 338). Scale bar = 10 mm. Photos by: Jonathan del Rosario.

FIGURE 32. Squamulose morphotype basidiome form of Pluteus rimosellus in situ (JAD 343). Scale bar = 10 mm. Photo by: Jonathan del Rosario.

FIGURE 33. Pluteus rimosellus. a. Basidiospores. b. Basidia. c. Basidioles. d. Pileipellis terminal elements. e. Cheilocystidia. f. Caulocystidia. g. Pleurocystidia. Scale bar = 10 µm. Drawings by: Jonathan del Rosario.

FIGURE 34. Basidiomes of Pluteus aff. semibulbosus (JAD 166). Scale bar = 10 mm. Photos by: Jonathan del Rosario.

FIGURE 35. Pluteus aff. semibulbosus a. Basidiospores. b. Basidia. c. Basidioles. d. Pileipellis terminal elements. e. Cheilocystidia. f. Caulocystidia. g. Pleurocystidia. Scale bar = 10 µm. Drawings by: Jonathan del Rosario.