Phylloporia warneckeicola Jerusalem, Yombiy., Amalfi & Decock, 2025

Phylloporia warneckeicola Jerusalem, Yombiy., Amalfi & Decock , sp. nov. MycoBank MB 851917. Figs 9C, E, F View Fig , 11 View Fig .

Etymology: “ warneckeicola ” (Latin) is referring to the host tree genus ( Warneckea Gilg. ).

Typus: Gabon, Ogooue Maritime Province, CTFS-ForestGEO Rabi forest monitoring Plot , ~ S1°55’28.56”, E9°52’48”, elev. ~ 30–60 masl, on the trunk of a small-stemmed living trunk, Warneckea floribunda ( Melastomataceae ), 2 May 2019, M. Jerusalem & P. Yombiyeni, MJ-GA19-017 (holotype BR; GoogleMaps isotype NY). GoogleMaps

Diagnosis: Phylloporia warneckeicola is similar to P. memecyli by the combination of small basidiomes (projecting 5–16 mm, 5–22 mm wide) emerging gregariously in clusters, mostly sessile, attached by a narrow dorsal point but closely following the substrate than appearing semicircular or broadly attached, and a densely, finely, concentrically sulcate pileus surface, but differs by a pore surface with a distinct greenish hue when fresh, smaller 11–13 pores / mm, 60–80 µm diam., and growing on Warneckea floribunda ( Melastomataceae ) in the understory of the Lower Guineo-Congolian rainforest.

Description: Basidiomes perennial, pileate, sessile (rarely with a stipe-like elongated base), gregarious, emerging simultaneously in clusters of up to 40 individuals, superposed, mostly solitary or 2–5 individuals imbricated; individual basidiome attached by a small apical or subapical, dorsal vertex, turbinate, pendant when young, but very closely to the bark, hence appearing a first sight semicircular to broadly attached, projecting firstly downward then horizontally, 5–16 mm, 3–22 mm wide, mostly semicircular or ellipsoid in outline, first slightly triquetrous when very small, progressively thinly applanate in transversal section, with the pores surface concave (incurved inside), with a general hard corky consistency; pileus surface shortly velutinous, finely, densely concentrically sulcate, with numerous fine sulcations (up to 10–12 very narrow concentric zones / cm), mainly brown (6E5, cocoa brown) to dark brown on aging (6F6, burnt amber), slightly lighter toward the margin (cinnamon brown); margin entire, thinly rounded, forming a well-defined, narrow rim especially in young basidiomes or surrounding patchy regrowth of pore field, greyish yellow when fresh, pale cork-coloured on drying; pore surface plane to mostly concave (incurved inside), first homogeneous, then with homogeneous or heterogeneous regrowth, in confluent, variably sized patches, brown or with a distinct greenish, olive green hue when very fresh, drying yellowish brown [5E(4–5) to 5F5, bronze, sooty brown, Havana brown]; pores small, regular, mostly round, sometimes slightly ellipsoid, 11–13(– 14) / mm, (50–)60–80(–90) µm diam. (av. = 69 µm diam.); dissepiments thin, (15–)20–50(–60) µm thick (av. = 31 µm); context homogeneous, dense, compact, 0.5–1.5 mm thick at the base, very thin to the margin, cinnamon brown to brown [6(D–E)6], topped by a thin black line subtending a thin upper trichoderm; trichoderm 125–250 µm thick, shortly velutinous (under the lens), agglutinating from the base, brown to dark brown (5E8); tube layer 0.5–1.5 mm deep, concolourous with the lower trama. Hyphal system dimitic; generative hyphae simple septate, thin- to slightly thick-walled, hyaline to faintly yellowish, scarcely branched, with a constriction at the branching point, 1.3–2.5 µm diam.; lower context, dominated by skeletal hyphae, parallel to long axis, tightly packed, arising from a generative hyphae and of limited growth, measured up to 250 µm long, 2.0–2.5 µm wide at the basal septa, progressively widening to (2.7–)3.2–4.0(– 4.3) µm wide (av. = 3.5 µm), golden brown, darker (brown) in alkali, thick- to very thick-walled with the lumen wide to narrow, mostly aseptate throughout, or with few secondary septa near the apices; trichoderm with prostrate to erected hyphae, mostly unbranched, thick-walled with widely open lumen, septate with both true and secondary septa, the apices rounded to open, yellowish to brown, mostly 4–6(–8) µm diam., the apices 6–8 µm wide; hymenophoral trama dominated by skeletal hyphae, mostly subparallel to the tube main axis, arising from a generative hyphae or a short mediate hyphae, mostly terminal, of limited growth, measured from 115 µm to 250 µm long, 1.8–2.5 µm diam. at the basal septa to (2.7–)3.2–4.0(–4.3) µm wide (av. = 3.5 µm) in the main part, occasionally geniculated in the basal lower third to mostly straight in the main part, occasionally locally inflated (up to 5–7 µm), or subapically constricted once or twice (slightly moniliform), slightly thick-walled at the basal septa, progressively thick- to very thick-walled, the lumen opening then narrow, locally lenticular, ending thin-walled, aseptate throughout but with a few secondary septa near the apices, golden brown, darker brown in alkali. Hymenium: Basidioles slightly pyriform to broadly clavate, 6.0–7.0 × 3.0–4.0 µm; mature basidia few, barrel-shaped to broadly clavate, with four sterigmata; cystidioles not seen; basidiospores ellipsoid to broadly ellipsoid, appearing somewhat angular on drying, thick-walled, smooth, hyaline to pale yellowish in KOH, without reaction in Melzer’s reagent, (3.0–)3.2–3.5(–3.8) × 2.2–2.5(–2.8) μm (av. = 3.4 × 2.4 µm), R = 1.3–1.5(–1.6) (ave Q = 1.4).

Phylogenetic affinities: The species, hitherto, is related to a group of morphologically and ecologically similar species, including P. warneckeicola , P. fulva , and P. pendula ( Fig. 1 View Fig ).

Ecology (substrate, host, habitat): On living trunk, small-stemmed Warneckea floribunda ( Melastomataceae ), understory compartment, Lower Guineo-Congolian rainforest.

Geographic distribution: Currently known from the CTFSForestGEO Rabi forest monitoring Plot, South-western Gabon.

Additional specimens examined: Gabon, Ogooue Maritime Province, CTFS-ForestGEO Rabi forest monitoring Plot , ~ S01°55’28.56”, E09°52’48”, elev. ~ 30–60 masl, on the trunk of a small-stemmed living tree, Warneckea floribunda ( Melastomataceae ), 15 Apr. 2012, C. Decock & P. Yombiyeni, GA-12-657; GoogleMaps ibid., 2 May 2019, M. Jerusalem & P. Yombiyeni MJ-GA19-020; 3 May 2019, M. Jerusalem & P. Yombiyeni MJ-GA19-048, MJ-GA19-049, MJ-GA19-050, MJ-GA19-055; 4 May 2019, M. Jerusalem & P. Yombiyeni MJ-GA19-057, MJ-GA19-064, MJ-GA19-069, MJ-GA19-070; 5 May 2019, M. Jerusalem & P. Yombiyeni MJ-GA19-072, MJ-GA19-073; 7 May 2019, M. Jerusalem & P. Yombiyeni MJ-GA19-088, MJ-GA19-089, MJ-GA19-092.

Notes: Phylloporia warneckeicola is closely related to P. memecyli , whatever the perspective. Both are related also to P. fulva , described from the same phytochorion in Gabon; these species belong to the same well-supported lineage ( Fig. 1 View Fig ). They also share most of their biology, including reproduction strategy, morphology, and some of their autecological parameters. They produce perennial, gregarious basidiomes, emerging in dense clusters ( Fig. 9 View Fig ), rather small (mostly around 10 mm radius, 1–3 mm thick at the base), mostly applanate, densely and very finely concentrically sulcate, shortly velutinous pilei ( Fig. 9 View Fig ), and small pores (~ 10–13 / mm). Their hyphal system, in the hymenophoral and context trama, could be considered as dimitic, with skeletal hyphae originating from a generative hyphae, occasionally from a mediate hyphae, and of a limited growth ( Figs 10 View Fig , 11 View Fig ), what is especially obvious in the hymenophoral trama. In the classification scheme of Corner (1991), it would be described as dimitic of the fifth degree (d5). The basidiospores are mostly ellipsoid, ~ 3.2–3.5 × 2.2–2.5 μm, av. 3.4 × 2.4 µm, ~ 3.5–4.0 × 2.2–2.5, av. 3.7 × 2.3, and ~ 3.0–3.5 × (2.2–)2.5–2.8 μm, av. 3.2 × 2.7 µm, respectively. They also share the substrate affinities and habitat: they grow from trunks of small-stemmed understory trees, which belong to the Melastomataceae in the case of P. warneckeicola and P. memecyli , and they inhabit the lower Guinean rain forest, at the westernmost edge of the larger Guineo-Congolian phytochorion. Phylloporia warneckeicola and P. memecyli are sympatric at least at the CTFS-ForestGEO Rabi plot in Gabon, an area of the Guineo-Congolian rainforest ( Anderson-Teixeira et al. 2014).

Phylloporia warneckeicola is abundant at a local scale, depending on the density of its host tree, W. floribunda View in CoL . In the 25 Ha of the CTFS-ForestGEO Rabi plot, W. floribunda View in CoL , with a density of ~ 110 individuals / Ha, represents the 14 th most abundant tree ( Memiaghe et al. 2016). Most of the individual trees present in an immediate neighbourhood are often hosting P. warneckeicola . Locally, P. memecyli is much less abundant, in parallel to its host tree, Memecylon viride View in CoL , which is not reported amongst the locally abundant understory tree ( Memiaghe et al. 2016).

Phylloporia warneckeicola and P. memecyli differ marginally by their pore surface colour, pores size, and basidiospores size; the pores surface in P. warneckeicola has a marked greenish brown tint (brown with greenish hue, bronze on drying), what is best seen in fresh, actively growing basidiomes, whereas it is mostly dark brown in P. memecyli ( Fig. 9C View Fig ); the pores are, respectively, mostly 11–13 vs 10–11 pores / mm; the basidiospores are slightly smaller in P. warneckeicola , 3.2–3.5 × 2.2–2.5 μm, av. 3.4 × 2.4 μm, vs 3.5–4.0 × 2.2–2.5 μm, av. 3.7 × 2.3 μm. The two species also differ in their host relationships, growing respectively from W. floribunda View in CoL and M. viride View in CoL . Phylloporia fulva View in CoL differs in having a paler pileus colour, greyish orange to pale cinnamon. Its host tree is unknown.

Phylloporia miomboensis (cf. discussion under this species) is similar in gross basidiome morphology but differs in having solitary basidiomes, and inhabiting a very distinct ecosystem. It is also phylogenetically distant ( Fig. 1 View Fig ).

Out of Africa, both P. warneckeicola and P. memecyli should be compared to P. pendula , which is biologically, morphologically, ecologically (Chen et al. 2017), and phylogenetically related ( Fig. 1 View Fig ). Phylloporia pendula differs from both African species in having larger pores, 7–9 / mm (Chen et al. 2017). Its geographic distribution and, pending confirmation, its host, could also differentiate it. Phylloporia pendula is known so far from Eastern, subtropical to tropical, continental and insular China but its host was not recorded (Chen et al. 2017).

The macro- and the micromorphology of the basidiomes of P. warneckeicola and P. memecyli also point toward P. pulla ( Yombiyeni et al. 2015) and P. subpulla ( Wu et al. 2019) . Yombiyeni et al. (2015) redescribed P. pulla based on examination of the type specimen, originating from Indonesia on an unidentified host. Phylloporia pulla is also, in literature ( Wu et al. 2019), reported from an unidentified host in Thailand. The species is represented, for the time being, by a single LSU sequence, from the above-mentioned Thai specimen (GenBank accession: MG738809 View Materials ), but the LSUbased phylogenetic inferences did not allow identifying any close relative ( Wu et al. 2019). This species differs from P. warneckeicola and P. memecyli in having broadly ellipsoid to subglobose basidiospores, mostly 2.8–3.5 × 2.3–2.8 µm (av. 3.0 × 2.6 µm).

Phylloporia subpulla View in CoL was described from tropical, continental and insular China ( Wu et al. 2019). It differs from P. warneckeicola and P. memecyli in having smaller pores, 13–16 / mm (vs ≤ 13 / mm in both African taxa), and smaller basidiospores, av. 2.7 × 2.0 μm ( Wu et al. 2019). Its phylogenetic affinities also are unknown ( Fig. 1 View Fig , Wu et al. 2019).