Phylloporia cinnamomea Decock, Yombiy., & Amalfi, 2025

Phylloporia cinnamomea Decock, Yombiy., & Amalfi , sp. nov. MycoBank MB 851872. Figs 4A–C View Fig , 5 View Fig .

Etymology: “ cinnamomea ” (Latin) in reference to the colour of the pileus.

Typus: Cameroon, East Provinces, Dja Biosphere Reserve, NW sector , 3 km South of Somalomo, ~ N03°01’31”, E12°59’59”, elev. ~ 675 masl, on an unidentified tree, 12–25 Sep. 2019, L. Ryvarden, LR 50722 (holotype O) GoogleMaps .

Diagnosis: Phylloporia cinnamomea is similar to P. rinoreae by the small, pileate, dimidiate basidiomes, roughly sulcate pilei, in cinnamon brown shade, presenting in section a comparatively thin, homogeneous context covered by a thin black line, subtending a comparatively thicker tomentum but differs in having slightly larger pores 8–9 / mm, (80–)85– 124(–130) µm wide (vs 9–10 / mm, 85–100 µm wide), and smaller basidiospores mostly 3.5–4.0 × 2.2–2.5 µm (vs 4.0– 4.5 × 2.5–3.0 μm).

Description: Basidiomes solitary, seasonal, pileate, sessile, semi-circular to dimidiate first, attached by the vertex, applano-convex in section, bent downward toward the margin, projecting 7–15 mm long, 10–20 mm wide, from 0.5–1 mm thick at the very margin up to 5–7 mm at the base or the attachment point (vertex); pileus surface tomentose, spongy, velvety to the touch, broadly sulcate with a few (1– 4) deep furrows near the base, more narrowly and densely sulcate near the margin, dull, mostly uniformly light brown to brown when dry [cinnamon to cocoa brown, 6(D–E)6, 6E(6–7)] (no data from fresh basidiomes but likely slightly darker), progressively darker near the margin (dark brown, 6F6); margin well-marked, forming a well-defined narrow rim, entire, regular in outline, greyish orange on drying; pore surface plane to mostly concave, the pore field starting immediately behind the very margin, mostly light brown when dry [5D(3–4) up to 5(D–E)6, honey yellow, oak brown, mustard brown]; pores regular, mostly round, 8–9 / mm, (80–)85–124(–130) µm wide (av. = 103.5 µm wide) when round, 110–130 × 90–100 µm when ellipsoid; dissepiments thin, entire, agglutinated, 20–50 µm thick (av. = 32 µm); in section, tomentum spongy, loose, brown, from 1 mm thick at the margin to 3 mm thick at the thickest part; context 0.2–1.0 mm thick toward the base or the attachment point, gradually thinning to the margin where it is very thin to absent, hard corky, shiny, light brown to brown, topped with a thin, dense black line, up to 100 µm thick, subtending the tomentum; tube layer up to 0.5–1.0 mm deep, light brown to brown; all parts darkening in alkali 3 %. Hyphal system dimitic in the context and hymenophoral trama, monomitic in the tomentum; generative hyphae simple septate, thin- to slightly thick-walled, hyaline to yellowish, scarcely ramified, the branches constricted at their emergence point, 1.5–3.0 µm diam. ( Fig. 5 View Fig ). In the tomentum, next to the black line, hyphae horizontal, with a near parallel orientation, soon variably mixed, horizontal to predominantly erected (vertical) and loosely packed, near the margin slightly incurving backward; individual hyphae mostly straight, rarely geniculated, locally with local swelling, mostly unbranched, or with a dichotomy, ending rounded, slightly thick-walled to thick-walled, the lumen> wall thickness, with both primary and secondary septa, hyaline first then yellowish to golden brown, from 2.5–3.0 µm diam. near the base gradually enlarging up to 3.5–5.5(–6.0) µm (av. = 4.2 µm diam.), swelling locally up to 7.5 µm; in the context, skeletal hyphae horizontal, with a near parallel orientation, golden brown, darker in KOH, moderately thick-walled with the lumen widely open, (2.5–)3.5–4.0 µm diam. (av. = 3.6 µm); in the hymenophoral trama, skeletal hyphae, born from a generative hyphae straight, of limited growth, 200–300 µm long, measured up to 350 µm, ending rounded, golden brown, darker in KOH, with a interwoven disposition, moderately thick-walled, the lumen ≤ wall thickness, aseptate or with occasional secondary septa, from 1.5–2.3 µm at the basal septum to 2.5–3.5 µm diam. (av. = 2.9 µm) in the main part, occasionally, locally inflated (up to 5µm). Hymenium: Basidioles slightly pyriform to clavate; mature basidia mostly clavate, 12.5 × 4.5 µm, with four sterigmata; cystidioles rare, fusiform; basidiospores oblong to elliptical (to broadly elliptical) in face view, the abaxial side straight to faintly incurved in side view, appearing slightly angular on drying, thick-walled, smooth, pale yellowish in KOH, without reaction in Melzer’s reagent, 3.5–4.0(–4.2) × (2.0–)2.2–2.5(–2.5) µm (av. = 3.9 × 2.3 µm), R = (1.4–)1.5–1.8(–2.0) (ave R = 1.7).

Phylogenetic affinities: The species, hitherto, is closely related to P. rinoreae , also known from the Guineo-Congolian rainforest in Western Gabon. Both species are affine to an unnamed species ( Phylloporia sp. PY-SN6), and to P. pseudoweberiana ( Fig. 1 View Fig ).

Ecology (substrate, host, habitat): Unknown plant organ, unidentified angiosperm, Guineo-Congolian rainforest.

Geographic distribution: Currently   GoogleMaps known from two spots of Guineo-Congolian   GoogleMaps rainforest, in Gabon (Ipassa-Makokou Biosphere Reserve, ~ N00°31’18”, E12°45’24”, elev. ~ 540 masl) and Cameroon (Dja Biosphere Reserve, ~ N03°01’31”, E12°59’59”, elev. ~ 675 masl).

Additional specimen examined: Gabon, Ogooue Ivindo Province , Ivindo National Park , Ipassa-Makokou Biosphere Reserve, Ipassa Biological Station, ~ N0°31’18”, E12°45’24”, elev. ~ 540 masl, small stem of unidentified angiosperm, Oct. 2016, P. Yombiyeni , YOM 5 ( BE) GoogleMaps .

Notes: Phylloporia cinnamomea is characterised by solitary basidiomes, a pileus in cinnamon brown shade, a thin, homogeneous, brown context and a comparatively thicker tomentum, both separated by a thin black line. In a morphological and phylogenetic perspective, P. cinnamomea is closely related to P. rinoreae . Both species share also the habitat, which is the Guineo-Congolian rainforest ( Jerusalem et al. 2019). These two species differ by their pore size, slightly smaller in P. rinoreae , basidiospores size, slightly shorter and narrower in P. cinnamomea (3.5–4.0 × 2.2–2.5, av. = 3.9 × 2.3 μm and 4.0–4.5 × 2.5–3.0 μm, av. = 4.3 × 2.7 μm). The host plant is unknown for P. cinnamomea .

Phylloporia cinnamomea and P. rinoreae could be compared also to P. pseudoweberiana , which belongs to the same clade (see notes under this species). These species share the basidiome anatomy and substrate affinities. Phylloporia cinnamomea and P. rinoreae have smaller basidiomes, up to 20 mm wide, whereas they are 20–80 mm wide in P. pseudoweberiana .