Ganoderma adspersum (Schulzer) Donk Proc. K. Ned. Akad. Wet., Ser. C, Biol. Med. Sci.
Index Fungorum number: 314302; Facesoffungi number: FoF05600
Basidiome annual, with a distinctly contracted base, non-laccate weakly laccate, woody. Pileus 10–15 × 4–7 cm, up to 4 cm thick at the base, flabelliform, plano convex, applanate, upper surface; hard, several layers thick, brownish orange (6C8) to light brown (6D4), crust overlies the pellis, concentrically sulcate zones with turberculate bumps and rivulose depressions, differentiated zone at the point of attachment. Margin soft, 5 mm thick, rounded, concolourous with the pileus, lower surface greyish yellow (4B3) to light brown (6D5). Hymenophore up to 10 mm long, indistinctly stratose, orange grey (6B2). Pores circular or sub-circular. Context up to 2.5 cm thick, dry, triplex; upper layer dark brown (7F8), pithy, composed of coarse loose fibrils, soft; lower layer light brown (5D4), woody. Basidiospores (n = 25) (7.2)8.5–9.6–10.5(10.9) × (4.8)5.4–6.1–7.3(7.8) μm, (Qm = 1.1, Q = 0.9–1.8, with myxosporium). (n = 25) (5.9)6.4–8.2–9.1(9.7) × (3.2)4.1–5.2–5.8(6.1) μm (Qm = 1.1, Q = 1.0–1.8, without myxosporium), yellowish brown (5D8), ovoid to subglobose, eusporium bearing fine, short, and distinct echinulae, overlaid by a hyaline myxosporium. Pileipellis a hymeniderm, dark brown (7F8), composed of apically clavate like branched cells. Context trimitic; generative hyphae (n = 25) (0.8–2.0–2.5) μm in width, thin-walled, hyaline; skeletal hyphae (n = 25) (1.8–3.4–4.2) μm in width, light brown (5D6), thick-walled; binding hyphae (n = 25) (1.4–3.1–3.9) μm in width, light brown (5D6), thick-walled, branched, intertwined the skeletal hyphae. (Fig. 1)
Habitat: On a living Dipterocarpus tree, accompanied in humus-rich soil with over heavily rotted litter on the ground.
Specimens examined: THAILAND, Chiang Mai Province, Mushroom Research Center, mixed deciduous forest, 19°20′N–98°44′E, elev. 770 m, 12 June 2015, K.K Hapuarachchi (GACP15061220, GACP15061225, GACP15061226).
Notes: Ganoderma adspersum is confused with G. applanatum, G. australe and Polyporus vegetus (Tortić 1971). Steyaert (1961) clearly separated this fungus from G. applanatum and he described this species under the name of G. europaeum. Donk (1969) concluded that the correct name of this fungus was G. adspersum after studying full description and drawings of Polyporus adspersus Schulzer, and Tortić (1971) subsequently followed this name. It is difficult to distinguish G. adspersum and G. applanatum on the basis of morphological characters of basidiome or mycelial cultures (Petersen 1987, Leonard 1998, Moncalvo et al. 2000, Terho et al. 2007, Kaliyaperumal & Pudupalayam 2008, De simone & Annesi 2012). However, Ganoderma adspersum is distinguished from G. applanatum by having larger basidiospores (Steyaert 1972, Ryvarden & Gilbertson 1993). Furthermore, basidiome of G. adspersum are usually thicker than G. applanatum at the base. The underside of the basidiome of G. adspersum has a decurrent attachment, while G. applanatum tend to emerge sharply at right angles from the host stem (Ryvarden & Gilbertson 1993, Schwarze & Ferner 2003). In a radial section of the hymenophore of the older parts of the basidiome, those of G. adspersum remain empty but the pores of G. applanatum become filled with a white mycelium (Breitenbach & Kränzlin 1986). Our collections agree well with the description provided by (Ryvarden & Gilbertson 1993). Later on, molecular methods have been developed successfully to separate the two latter species (Gottlieb et al. 2000, Moncalvo et al. 2000, Guglielmo et al. 2008, De Simone & Annesi 2012, Arulpandi & Kalaichelvan 2013, Zhou et al. 2015, Jargalmaa et al. 2017).
Some researchers considered the correct name of the G. adspersum as a synonym of G. australe (Ryvarden 1976, Ryvarden & Gilbertson 1993). Furthermore, morphology, distribution and initial ribosomal sequence analysis could not separate G. adspersum from G. australe (Moncalvo et al. 1995a). But comparison of ITS rDNA data clearly separated the G. adspersum from G. australe and was inferred as single species (Smith & Sivasithamparam 2000).
Ganoderma adspersum has been recorded almost exclusively on hardwoods causing butt rot or root rot (De Simone & Annesi 2012). Ganoderma adspersum and G. applanatum differ in their ability to break through the reaction zones formed in infected trees. Ganoderma adspersum can penetrate intact reaction zones of infected wood blocks, while G. applanatum cannot. In the absence of reaction zones, however, G. applanatum causes more extensive and intense decay (Schwarze & Ferner 2003). Hence, the correct identification of the causal agent is important for a reliable assessment of the potential risks caused by infected trees. (from Hapuarachchi K et al 2018)