Ganoderma casuarinicola

Ganoderma casuarinicola J.H. Xing, B.K. Cui & Y.C. Dai. in Xing, Sun, Han, Cui & Dai

Index Fungorum number: xxx; Faces of fungi number: FoF 06130

Basidiocarps Substipitate to stipitate. Pileus shape. Annual, applanate and dimidiate when becoming mature, up to 10–16 cm in length, 4–9 cm in width, up to 0.7–1.2 cm thick. Pileus surface. Distinctively zonate from the base to the margin where the new hyphae are in active development, orange, golden yellow at the base, slightly to reddish-orange, orange-red, brownish-red, extended to reddish-brown, red at centre, orange to deep orange extending to the upper margin surface, with yellowish-white to pale yellow under margin surface, strongly laccate, glabrous, glossy, shiny, smooth, spathulate, shallow sulcate when fresh, thin-crust overlies the pellis, thicker at the base than the margin, light in weight when dried, non-woody when dried. Context. Mostly yellow to light orange, orange close to crust, reddish-golden, light brown, brown near the tube layers, dense context layer but not fully homogeneous, thick near the base, tough to break when dried; generative hyphae up to 2.10–4.92 μm (`x = 3.34, n = 50) in diam., thin-walled, almost colourless, some expanded at the apex, unbranched, with clamp connections; binding hyphae 3.67–5.93 µm (`x = 4.85, n = 50), almost colourless, thin to thick-walled, branched, with clamp connections; skeletal hyphae abundant, up to 3.49–7.34 μm (`x = 5.34, n = 50), almost colourless, thick-walled, unbranched or with very few branches in the distal end, without clamp connections. Hymenophore. Trimitic, heterogeneous, up to 1.4 cm thick, generally yellow slightly to light orange, up to 4 mm thick, the lower layer (close to the tubes) on the upper layers, light brown to brown close to the tubes, presented dark brown, melanoid band. Basidiospores. Ellipsoid to broadly ellipsoid with double-wall (ganodermoid) at maturity, yellowish-brown, (8.7)10.8–13.5(14.4) × (6.6)7.6–8.9(9.8) μm (`x = 12.05 × 7.8 μm, n= 50), with Q = 1.38 – 1.45, L = 11.68 µm, W = 8.25 µm (including myxosporium), (7.1)9.9–11.2(12.1) × (5.2)6.7–7.3(8.9) μm (`x = 10.2 × 6.4 μm, n = 50) μm, with Q = 1.48–1.52, L = 10.65 µm, W = 7.10 µm (excluding outer myxosporium). Tubes. Up to 6–14 mm long, dark brown, hard, woody when dried; generative hyphae 1.0–3.7 µm in diam., occasionally with simple septa, almost colourless, thin-walled with occasionally thick walls, with clamp connections, occasionally branched; skeletal hyphae 2.7–5.1 µm in diam., thick-walled frequently branched at apex; binding hyphae 1.1–3.0 µm in diam., thin to thick-walled, frequently branched at apex. Stipe. Lateral, golden yellow, orange-red, up to 8 cm long, 1.8 cm in diam. Margin. Obtuse from the substrate, soft, slippery to the touch when young, tough to break. Pores. Angular to round, 4–6 per mm, up to 128–195 × 148–266 µm (`x = 162 × 220 μm, n = 50). Pore surface. White when fresh, turning yellowish-white to pale yellow when dry, reddish-grey when touched, greyish-brown, brownish-grey when wet. Hyphal system. Trimitic, generative hyphae, 2–5 µm in diam., almost colourless, thin-walled or occasionally thick-walled, with clamp connections, occasionally with irregular cuticle cells, light brown to brown in KOH; binding hyphae 3–5 µm, almost colourless, thin to thick-walled, branched, with clamp connections; skeletal hyphae abundant, up to 3–7 μm, almost colourless, thick-walled, unbranched, without clamp connections. (Fig. 1)

Habitat: Solitary on Pinus kesiya stumps in pine forests.

Specimen examined: THAILAND, Surat Thani Province, Phanom District, 8°54'32"N, 98°31'09"E, 427 m elev., 25 June, 2018, LT2018-103 (HKAS 104639).

      Notes: Ganoderma casuarinicola was introduced from China recently, based on molecular and morphological data (Xing et al. 2016). This species causes white rot in Casuarina equisetifolia plants (Xing et al. 2016). Ganoderma casuarinicola is characterized by its strongly laccate reddish-brown pileal surface, white pore surface, and luminous yellow to yellowish-brown cutis (Xing et al. 2016).