Pluteus wahei, Del, Jonathan A. & Perry, Brian A., 2025

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 : 32-33

Pluteus wahei J.A. del Rosario & B.A. Perry, sp. nov. ( Figs. 13 , 14 )

MycoBank no.:—854223

Holotype:— VANUATU. Tafea Province: Tanna, Yakuwan , 19°32.230′S, 169°28.911′E, elev. 116 m, 19 August 2019, coll. J. A. del Rosario & B. A. Perry, JAD 284 ( HAY).

Etymology:—Named in honor of Jean-Pascale Wahe, head of the Tafea Kaljoral Senta, for his long-time collaboration with the Plants mo Pipol blong Vanuatu project. Born and native to Tanna, this is reflected in the species’ occurrence being known only from Tanna.

Diagnosis:— Pluteus wahei is characterized by a tawny brown appressed-fibrillose, dark umber disc, marginally sulcate pileus, and a silky white stipe. Some forms have a pileus that lack a distinct disc and are a paler shade of brown overall. Microcharacters include subglobose spores (5.8 × 4.5 µm), clavate cheilocystidia, fusoid-ventricose, thick-walled pleurocystidia with apical hooks, similar smaller intermediate pleurocystidia but with lateral outgrowths, a cutis pileipellis, absence of caulocystidia, and the presence of clamp connections in all tissues.

Description:— Pileus 30–45 mm diam., convex to broadly plano-convex, slightly umbonate with a small central depression, margin slightly sulcate; surface dull turning pellucid-striate at the margin, dry, densely appressed-fibrillose or glabrous, disc punctate or rugulose; disc dark umber, fibrils tawny brown (oac721–oac722), densest at disc becoming sparse towards margin, or some forms glabrous overall and pale gray-tan to almost off-white without a distinct disc. Context up to 5 mm thick, white. Lamellae free, moderately crowded with 3 tiers of lamellulae, thin, off-white to pale pink (oac696–oac697). Stipe 40–70 × 3–4 mm, central, terete, cylindrical, solid; surface pearlescent, dry, silky, white overall, context white. Odor indistinct. Taste indistinct.

Basidiospores 5–7 (–8) × 4–5 (–6) µm [x mr = 5.62–5.94 × 4.1–4.84 µm, x mm = 5.78 ± 0.22 × 4.47 ± 0.09 µm, Q = 1–1.6 (–2), Q mr = 1.24–1.38, Q mm = 1.31 ± 0.09, n = 50, s = 2], subglobose to broadly ellipsoid, smooth, hyaline, with a guttule, inamyloid, thick-walled. Basidia 18–29 × 4–8 µm, clavate, 4-spored, hyaline, thin-walled, sterigmata 2–4 × 0.5–1 µm. Basidioles 11–24 × 4–8 µm, clavate, hyaline, thin-walled. Cheilocystidia 28–58 × 8–22 µm, clavate to cylindro-clavate, seldom fusoid-ventricose, obtuse or rarely umbonate, hyaline, thin-walled. Pleurocystidia; primary pleurocystidia (56–) 65–80 (–96) × 14–20 µm, lageniform to fusoid-ventricose, cornuate with 2–4 whole, straight to recurved seldom poorly or well-developed apical hooks, rarely with 1–2 lateral excrescences, hyaline, thick-walled; intermediate pleurocystidia 31–56 (–70) × 10–16 µm, similar to primary but smaller and thinner-walled, lageniform to fusoid-ventricose, frequently corniculate with 1–3 blunt, poorly developed apical hooks or occasionally cornuate with 1–3 straight to recurved well-developed hooks, occasionally with 1–3 lateral excrescences, hyaline, thin to thick-walled. Pileipellis a cutis of repent hyphae, composed of hyaline or with pale brown plasmatic pigment, non-incrusted, non-gelatinous, thin-walled, cylindrical hyphae, 8–22 µm diam.; terminal cells 50–112 × 7–16 µm, repent to suberect towards disc, clavate to filiform, obtuse to capitate, some entirely nodulose. Pileus trama interwoven, composed of hyaline, non-gelatinous, thin-walled, cylindro-clavate hyphae, 5–30 µm diam.. Lamellar trama inverse, composed of hyaline, non-gelatinous, thin-walled hyphae, 4–12 µm diam.. Stipitipellis a cutis, composed of hyaline, non-incrusted, non-gelatinous, thin-walled hyphae, 5–18 µm diam.. Caulocystidia absent. Clamp connections present in all tissues examined.

Habitat and known distribution:—Gregarious on decaying wood in subtropical lowland mixed-use agro tree garden and disturbed secondary broadleaf rainforest containing Cocos nucifera ( Arecaceae ), Cordia subcordata ( Boraginaceae ), Leucaena leucocephala ( Fabaceae ), Macaranga dioica ( Euphorbiaceae ), and Syzygium malaccense ( Myrtaceae ) and primary broadleaf rainforest containing Dysoxylum aneityense ( Meliaceae ), Ficus adenosperma ( Moraceae ), Hedycarya dorstenioides ( Monimiaceae ), Inocarpus fagifer ( Fabaceae ), Kermadecia lutea ( Proteaceae ), Macaranga dioica ( Euphorbiaceae ), Myristica fatua ( Myristicaceae ), and Syzygium myriadenum ( Myrtaceae ), Vanuatu (Tanna).

Material examined:— VANUATU. Tafea Province: Tanna, at Transect 7, Kwaprapra , Iatukwei , 19°34.255′S, 169°27.093′E, elev. 252 m, 11 December 2017, coll. J. A . del Rosario, JAD 107 ( HAY); Tanna, Yakuwan , 19°32.230′S, 169°28.911′E, elev. 116 m, 19 August 2019, coll. J. A . del Rosario & B. A . Perry , JAD 284 ( HAY) .

Notes:—Historically there has been difficulty in identification and taxonomy of certain species in sect. Pluteus , especially when some pigmented species like P. cervinus (Schaeffer) Kummer (1871: 99) or P. pouzarianus Singer (1983: 283) are known to produce pure white or paler-colored morphotype variants ( Justo et al., 2014). The use of microcharacteristics in combination with molecular data has been crucial for the taxonomy of this group. Pluteus wahei produces basidiomes with pale forms that may resemble a number of species. The Sri Lankan P. aglaeotheles (Berkeley & Broome) Saccardo (1887: 676) produces a pale basidiome and shares similarly sized and shaped spores and pleurocystidia with P. wahei , but differs significantly due to the lamellar edge containing metuloid cystidial elements, the pileipellis lacking nodulose elements, and clamp connections being absent ( Pegler 1986, Singer 1956). Pluteus brunneidiscus Murrill (1917: 131) was noted to have lateral outgrowths on the terminal cells of the pileipellis, but compared to P. wahei has larger spores, seldom has lateral outgrowths on the cystidia, and has a superficially different squamulose pileus ( Banerjee & Sundberg 1993, Justo et al. 2014, Singer 1956). The dark pigmented pileus form of P. wahei is comparable to tropical species such as P. subcervinus (Berkeley & Broome) Saccardo (1887: 666) and P. fibulatus Singer in Singer & Digilio (1952: 252). Pluteus subcervinus was originally described from Sri Lanka ( Berkeley & Broome 1871) and since then has been reported from Tanzania ( Pegler 1977), Indonesia (according to Pegler 1986), India ( Pradeep et al. 2002), and recently Vietnam ( Malysheva et al. 2020). Pluteus subcervinus differs from P. wahei in having a non-nodulose pileipellis, highly branched pleurocystidia, and in producing a paler camel brown pileus. Pluteus fibulatus tends to produce a darker brown pileus and stipe, has more apically variable pleurocystidia and non-nodulose pileipellis cells ( Campi et al. 2019, Singer 1958, Singer & Digilio 1952).

Phylogenetic analysis of ITS data ( Fig. 1b ) places P. wahei on a supported branch, sister to the petasatus clade ( BS 100 %, PP 1.0) with a recently described taxon P. olivaceofibrillosus E.F. Malysheva & A.V. Alexandrova (2020: 84) . Pluteus wahei separates itself from species of Justo et al. ’s (2014) petasatus clade by the presence of clamp connections on the pileipellis compared to a lack of clamp connections in P. petasatus and P. leucoborealis Justo, E.F. Malysheva, Bulyonkova & Minnis (2014: 58) , a non-pigmented stipe, pleurocystidia with lateral hooks, nodulose pileipellis cells, and lack of a squamulose disc compared to P. pellitus (Persoon) Kummer (1871: 98) . The pileus color of the pale morphotype of P. wahei strongly resembles the Vietnamese P. olivaceofibrillosus , but differs from this taxon in lacking a distinct disc. Both color variants of P. wahei share a sulcate margin and have a striate fibrillose pileus similar to P. olivaceofibrillosus , but the pigmented morphotype mainly differs in having a darker, tawny brown pileus. Micromorphologically, both species share multiple characters, but ultimately P. wahei is separated by the intermediate pleurocystidia having lateral hooks and a mix of poorly to well-developed apical hooks rather than being only mucronate, and the pileipellis terminal elements being nodulose and capitate ( Malysheva et al. 2020). Pluteus wahei is recognized as a distinct species from P. olivaceofibrillosus and described as new due to the morphological differences in combination with phylogenetic data.

Figures

FIGURE 1a–d. Maximum Likelihood phylogeny of sect. Pluteus based on ITS sequence data (-lnL = 6609.645735). 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 13. Basidiomes of Pluteus wahei (JAD 284 holotype). Scale bar = 10 mm. Photo by: Jonathan del Rosario.

FIGURE 14. Pluteus wahei. a. Basidiospores. b. Basidia. c. Basidioles. d. Pileipellis terminal elements. e. Cheilocystidia. f. Intermediate pleurocystidia. g. Primary pleurocystidia. Scale bar = 10 µm. Drawings by: Jonathan del Rosario.