Erythrophylloporus paucicarpus Raspe , Vadthanarat & 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 paucicarpus Raspe, Vadthanarat & Lumyong sp. nov. Figs 2A, 3A, 4Aand 5

Holotype.

THAILAND, Chiang Mai Province, Mae On District, Huay Kaew, 18°52'0"N, 99°17'30"E, elev. 700 m, 16 August 2016, O. Raspé & S. Vadthanarat, OR1151, (holotype: CMUB, isotype: BR).

Etymology.

from Latin “pauci-” meaning few and “carpus” meaning fruits or what is harvested, refers to the low number of basidiomata produced.

Description.

Basidiomata stipitate-pileate with lamellate hymenophore, small to medium-sized. Pileus 2.3-5.5 cm in diameter, plano-convex with involute margin at first becoming almost plane to slightly depressed with inflexed to straight margin, irregularly and coarsely crenate in age, sometimes with low and broad umbo and a few to several verrucae, especially when young; surface more or less even, tomentose, dull, slightly moist, colour distribution patchy with red to brownish-orange (9B8 to 9C8), brownish-red (10E8 to 10D8) becoming orange-red to orange (8B/C8 to 6B7) at the margin when old, abruptly paler at the margin. Pileus context 3-4 mm thick half-way to the margin, tough, colour distribution even, yellow (3A6) to yellowish-orange (4A5), slowly reddening when exposed, especially at the centre and above lamellae. Stipe 2.4-4.5 × 0.7-1.3 cm, central or sometimes slightly eccentric, clavate with strigose base, straight to curved, terete, even, dull, dry, tomentose, yellowish-orange (4 –5A7– 8) to orange (6 –7A7– 8) with orange to yellowish-orange (7B/C7-8 to 4A7-8) coarse scales, with bright yellow (2A6-7) basal mycelium. Stipe context solid, fleshy fibrous, yellow marbled with olivaceous brown (4D5, 5D5). Hymenophore lamellate; lamellae decurrent, close, thick, 40-42 lamellae, with 4-6 different lengths of lamellullae, 2-4.5 mm wide half-way to margin, somewhat anastomosing, especially near the stipe, yellowish-orange (4-5A6-7) with orange to red tinge, slightly reddening when bruised. Odour rubbery; Taste not recorded. Spore print olive-brown (4E7).

Macrochemical reactions. KOH on pileus and stipe surface deep red at first, then red-brown to brown, with pale orange aura on the pileus; brown on pileus context, dark red-brown on stipe context; brownish-orange on hymenophore. NH4OH on pileus first red, then orange; on pileus context bluing at first then with a greenish tinge; on stipe surface and context briefly bluing; no reaction on hymenophore.

Basidiospores [208/4/4] (5.9 –)6.1–6.8–7.5(– 8) × (4.1 –)4.6–5.1–5.5(– 6) µm, Q = (1.2 –)1.23–1.33–1.48(– 1.56); from the type (OR1151) (6 –)6.3–6.8–7.5(– 7.8) × (4.6 –)4.8–5.2–5.5(– 6) µm, Q = (1.2 –)1.22–1.31–1.48(– 1.56), N = 88, broadly ellipsoid to ellipsoid, smooth under light microscope and SEM, yellowish to pale brown in water, hyaline in 5% KOH, thin-walled, inamyloid. Basidia 4-spored, (37.8 –)38–45.6–54.7(– 54.8) × (6.2 –)–6.3–8–9.5(– 9.6) 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 5.5 µm long. Cheilocystidia (35.4 –)35.5–49.9–61.8(– 61.9) × (3.9 –)3.9–6–7.7(– 7.7) µm, narrowly fusiform with obtuse apex, projecting up to 30 µm, thin-walled, smooth, yellowish hyaline in water, in 5% KOH and NH4OH, inamyloid. Pleurocystidia (66.9 –)67.4–80.3–93.5(– 94.7) × (8.8 –)8.9–11.7–16.1(– 16.2) µm, abundant, narrowly conical with obtuse, somewhat prolonged apex, projecting up to 32 µm, thin-walled, smooth, yellowish hyaline in water, in 5% KOH and NH4OH, arising more or less deeply in the subhymenium or from hymenophoral trama, inamyloid. Hymenophoral trama subregular near the pileus context becoming slightly divergent near the edge, 87-238 µm wide, widest near the pileus context then getting narrower when close to the edge, composed of clampless hyphae 4.5-8 µm wide, yellowish hyaline in water, hyaline in 5% KOH and NH4OH. Pileipellis a palisadoderm to trichoderm 83-165 µm thick, composed of slightly thick-walled, cylindrical hyphae, terminal cells 16-46 × 4-6.5 µm with rounded apex, hyaline or yellowish hyaline to yellowish-orange hyaline hyphae ornamented with scattered fine epiparietal encrustation when observed in water, hyaline to yellowish hyaline in 5% KOH and NH4OH, inamyloid. Pileus trama composed of slightly thick-walled, strongly interwoven hyphae, 4.5-8.5 µm wide, inamyloid. Stipitipellis a disrupted palisadoderm perpendicular to the stipe axis, 63-145 µm thick, composed of slightly thick-walled, slightly rough, cylindrical, yellow to yellowish-orange in water, yellowish hyaline hyphae in 5% KOH and NH4OH, terminal cells 13-57 × 3-8 µm, cylindrical to irregular hyphae with rounded to notched apex; wall covered by dispersed fine encrustations when observed in water. Caulocystidia not seen. Stipe trama composed of parallel hyphae, densely packed, 4-8.5 µm wide; hyphae wall covered by dispersed encrustations when observed in water. Clamp connections not seen in any tissue.

Habit and habitat.

On soil, mostly solitary in dipterocarp forest dominated by Dipterocarpus tuberculatus , D. obtusifolius , Shorea obtusa , S. siamensis , Quercus spp. and Lithocarpus spp.

Known distribution.

Currently known only from Chiang Mai Province, northern Thailand.

Additional specimens examined.

- THAILAND, Chiang Mai Province, Muang District, Doi Suthep-Pui National Park, 18°48'05" N– 98°55'40"E, elev. 800 m, 17 May 2015, O. Raspé, OR0615A (CMUB, BKF, BR); Mae Taeng District, Baan Tapa, 19°08'29"N, 98°45'47"E, elev. 1035 m, 4 August 2015, O. Raspé & A. Thawthong, OR0689 (MFLU, BR); Mae On District, Huay Kaew, 18°52'12"N, 99°18'12"E, elev. 780 m, 15 August 2016, O. Raspé & S. Vadthanarat, OR1135 (CMUB, BR).

Remarks.

E. paucicarpus is characterised by the following combination of features: orange to brownish- to orange-red basidiomata, yellowish-orange lamellae that turn slightly red when bruised; pileus context yellow to yellowish-orange that slowly reddens when exposed and mostly occurring as solitary basidiomata.

In the inferred molecular phylogeny, E. paucicarpus clustered close to E. suthepensis and E. cinnabarinus (65% BS and 1 PP), but the two species are different from E. paucicarpus in that they have darker lamellae which are orange to orange red or brownish-orange. Moreover, spores of E. paucicarpus are wider and longer (5.9-8 × 4.1-6 µm) than those of E. suthepensis (4.6-5.9 × 3.5-4.5 µm) and, on average, longer than those of E. cinnabarinus (5.5-7 × 4.5-5.5 µm) ( Zhang and Li 2018). Erythrophylloporus paucicarpus also differs from both species by the slight reddening of the context and lamellae when exposed or bruised, whereas E. suthepensis context seems unchanging when exposed and lamellae turn blue when bruised. In E. cinnabarinus , the context slowly turns dark violet, blackish-blue to dark blue when exposed and lamellae turn greyish-blue, or greyish-green when bruised ( Zhang and Li 2018).

Erythrophylloporus paucicarpus is different from the two New World species by the reddening of the context, whereas in E. fagicola , it turns blue and, in E. aurantiacus , the colour remains unchanged when exposed. Moreover, E. fagicola has somewhat thick-walled (0.8-3.5 µm) pleurocystidia ( Montoya and Bandala 2011), which are not found in E. paucicarpus . Although the basidiospores of E. paucicarpus and E. aurantiacus are similar in size ( E. aurantiacus = 6.0-7.5 × 4-5.5 µm), they differ in shape, being more ovoid in E. aurantiacus than in E. paucicarpus . Erythrophylloporus paucicarpus also differs from E. aurantiacus by macro-chemical reactions. In the latter, the pileus surface and pileus context are unchanging with NH4OH ( Halling et al. 1999), while in E. paucicarpus , the pileus becomes orange to red and the pileus context initially turns blue then with a greenish tinge.