Erythrophylloporus suthepensis Vadthanarat, Raspe & Lumyong

Vadthanarat, Santhiti, Amalfi, Mario, Halling, Roy E., Bandala, Victor, Lumyong, Saisamorn & Raspe, Olivier, 2019, Two new Erythrophylloporus species (Boletaceae) from Thailand, with two new combinations of American species, MycoKeys 55, pp. 29-57 : 29

Erythrophylloporus suthepensis Vadthanarat, Raspe & Lumyong sp. nov. Figs 2B, 3B, 4Band 6

Holotype.

THAILAND, Chiang Mai Province, Muang District, Doi Suthep-Pui National Park, 18°48'47"N, 98°55'56"E, elev. 645 m, 25 August 2015, S. Vadthanarat, SV0236, (holotype CMUB, isotype BKF, BR).

Etymology.

Refers to the type locality Doi Suthep.

Description.

Basidiomata stipitate-pileate with lamellate hymenophore, small-sized. Pileus (1.0 –)2.5– 3.5 cm in diameter, subumbonate with involute margin at first, becoming convex to plano-convex with inflexed margin; surface even with some small pustules, tomentose, dull, slightly moist, yellow (3 –4A4– 5) becoming light orange to orange-red (5 –6A5– 7 to 7 –8A–B7– 8) with patches of light yellow to light orange (4 –5A5– 6) becoming brownish-orange to dull red (7 B–C 8 to 8 B–D 8) with age, the colour of the margin when young clearly paler than the rest of the pileus, bluing when bruised. Pileus context 2-3 mm thick half-way to the margin, tough, yellowish-orange (4A5), unchanging when bruised. Stipe 2.5- 4.5 × 0.3- 0.8 cm, central, slightly curved, terete, dull, dry, yellowish-orange (2A6-7) with greyish-orange (5-6 B 7-8) coarse scales at first, then light yellow or reddish-yellow to brownish-orange (4A/B5-6 to 7C6) with brownish-red to reddish-dark brown (7F4-5, 8C7-8, 8F5-7) scales, sub-bulbous, with bright yellow to greyish-yellow (2A6-7 to 3A/B5-6) sparse basal mycelium that extends half-way up the stipe. Stipe context solid, tough, reddish-yellow (4A6) near the pileus then paler to light yellow (4A5) near the base, unchanging when bruised. Hymenophore lamellate; lamellae decurrent, subdistant, slightly thick, with sinuate edge, of varying lengths, 26-34 lamellae, with 4-6 different lengths of lamellullae, 4-5 mm wide half-way to margin, brownish-orange (7C7-8) with deep yellow to orange (4 –5A7– 8) edge, bluish-grey when looking tangentially to the surface, bluing when bruised. Odour rubbery. Taste mild with rubbery texture. Spore print olivaceous brown (4F5).

Macrochemical reactions. KOH orange-brown on pileus and stipe surface; yellowish-brown on pileus and stipe context and hymenophore. NH4OH yellowish-brown on pileus and stipe surface and hymenophore; yellowish on pileus and stipe context.

Basidiospores [218/4/2] (4.6 –)4.8–5.2–5.7(– 5.9) × (3.5 –)3.6–4–4.3(– 4.5) µm, Q = (1.15 –)1.21–1.32–1.44(– 1.57); from the type (SV0236) (4.6 –)4.8–5.2–5.7(– 5.9) × (3.5 –)3.6–3.9–4.4(– 4.5) µm, Q = (1.15 –)1.21–1.32–1.43(– 1.57), N = 80, broadly ellipsoid to subglobose, smooth under light microscope and SEM, yellowish to pale brown in water, hyaline in 5% KOH, thin-walled, inamyloid. Basidia 4-spored, (24.7 –)25.3–31.1–35.8(– 35.9) × (5.3 –)5.3–6.6–7.5(– 7.5) µm, narrowly clavate to subcylindrical, attenuated towards the base, clampless, hyaline to yellowish hyaline in water, Melzer’s reagent and 5% KOH; sterigmata up to 4.5 µm long. Cheilocystidia (37.3 –)37.9–51–63.8(– 64.1) × (5.3 –)5.4–8.5–12.4(– 13.7) µm, narrowly conical to narrowly fusiform with obtuse apex, projecting up to 25 µm, thin-walled, smooth, yellowish-hyaline in water, hyaline in 5% KOH and NH4OH, inamyloid, more or less forming a sterile edge. Pleurocystidia (46.5 –)49.2–68.9–95.2(– 99.3) × (9.3 –)9.6–12.6–18.9(– 20) µm, abundant, narrowly conical with obtuse apex, projecting up to 28 µm, thin-walled, mostly yellowish hyaline in water and hyaline in 5% KOH and NH4OH, some containing yellowish-brown to dark brown pigments in water and yellowish-pale brown in 5% KOH and NH4OH, inamyloid, arising more or less deeply in the subhymenium or from hymenophoral trama. Hymenophoral trama subregular near the pileus context becoming slightly divergent near the edge, 46-192 µm wide, widest near the pileus context then getting narrower when close to the edge, composed of clampless hyphae 2.5-7.5 µm wide, pinkish-red hyaline in water, especially at the centre of the trama, yellowish hyaline to hyaline in 5% KOH and NH4OH. Pileipellis a palisadoderm to trichoderm 71-119 µm thick, composed of slightly thick-walled, cylindrical to irregular hyphae with fine encrustation on the wall, terminal cells 12-46 × 3.5-9 µm with pointed to notched apex or sometimes truncated apex, with 6 –15(– 28) µm short cells at the base, hyaline or yellowish-orange hyaline to orange hyaline hyphae with scattered fine encrustation on the wall when observed in water, hyaline to yellowish hyaline in 5% KOH and NH4OH, inamyloid. Pileus context composed of slightly thick-walled, strongly interwoven hyphae, 5-8.5 µm wide, inamyloid. Stipitipellis a disrupted palisadoderm perpendicular to the stipe axis, 47-123 µm thick, composed of slightly thick-walled, cylindrical to irregular hyphae with fine encrustations on the wall, yellow to yellowish-orange, intermixed with mostly yellowish hyaline to yellowish-brown hyphae in 5% KOH and NH4OH, terminal cells 14-47 × 4-8.5 µm with variously notched apex. Caulocystidia mixed in a group with the stipitipellis hyphae, same shape and size as the pleurocystidia, dark brown in water, paler in 5% KOH and NH4OH. Stipe context composed of parallel, densely packed, 4-9.5 µm wide hyphae, hyphae wall with scattered fine encrustations when observed in water. Clamp connections not seen in any tissue.

Habit and habitat.

On soil, gregarious (up to 10 basidiomata) in dipterocarp forest dominated by Dipterocarpus tuberculatus , D. obtusifolius , Shorea obtusa and S. siamensis , mixed with scattered fagaceous trees.

Known distribution.

Currently known only from Doi Suthep-Pui National Park, Chiang Mai Province, northern Thailand.

Additional specimens examined.

- THAILAND, Chiang Mai Province, Meuang District, Doi Suthep-Pui National Park, 18°48'05"N, 98°55'40"E, elev. 800 m, 17 May 2015, O. Raspé, OR0615B (CMUB, BKF, BR).

Remarks.

Erythrophylloporus suthepensis is characterised by the following combination of features: yellow to light orange to orange red to brownish-orange to dull red pileus; brownish-orange lamellae with deep yellow to orange edge; the colour of the lamellae appears more bluish-grey when observed from an oblique angle to the surface; pileus surface and lamellae turning blue when bruised; some pleurocystidia containing yellowish-brown to dark brown pigments in water; basidiospores that are smaller or shorter (4.6-5.9 × 3.5-4.5 µm) than the other Erythrophylloporus species ( E. aurantiacus = 6.0-7.5 × 4-5.5µm; E. cinnabarinus = 5.5-7 × 4.5-5.5 µm; E. fagicola = 6.5-11 × 4-7.5 µm; E. paucicarpus = 5.9-8 × 4.1-6 µm) ( Halling et al. 1999, Montoya and Bandala 2011, Zhang and Li 2018).

Morphologically, E. suthepensis is quite similar to E. cinnabarinus in that they have similar colours in pileus and lamellae; the lamellae in both species also turn more or less blue to dark blue when bruised. Erythrophylloporus suthepensis and E. cinnabarinus are also similar, based on some pleurocystidia containing yellowish-brown to dark brown pigments, but those features are not found in E. paucicarpus and in the two New World Erythrophylloporus species ( Halling et al. 1999, Montoya and Bandala 2011). However, the pleurocystidia containing brown pigments seem to be more frequent in E. cinnabarinus , which also has, on average, larger basidiospores than E. suthepensis ( Zhang and Li 2018).

The pinkish-red hymenophoral trama of E. suthepensis was not found in either E. paucicarpus or in the two American Erythrophylloporus species. In our observation of the two American specimens ( E. aurantiacus voucher REH7271 and E. fagicola voucher Garay215), we found that the hymenophoral trama was yellowish hyaline when observed in water. The original description of E. cinnabarinus does not mention the colour of the hymenophoral trama and we could not obtain a specimen to observe this character. However, other morphological characters and phylogenetic evidence are enough to differentiate E. suthepensis from E. cinnabarinus .

Our phylogenetic analyses of a four-gene dataset revealed that Phylloporus aurantiacus from Costa Rica and P. fagicola from Mexico clustered in the Erythrophylloporus clade with high support (BS = 100% and PP = 1). Both species possess the distinctive morphological characters of Erythrophylloporus , which include yellowish-orange to reddish-orange basidiomata, orange to orange brown lamellae, bright yellow basal mycelium, ovoid or ellipsoid to broadly ellipsoid basidiospores with smooth surface and subcylindrical to subfusoid to ventricose cheilocystidia and pleurocystidia ( Halling et al. 1999, Montoya and Bandala 2011). Therefore, the following two new combinations are proposed: