Suillus phylolaricinus R. Zhang, X. F. Shi, G. M. Mueller & P. G. Liu, 2025

Shi, Xiaofei, Zhang, Shiru, Mueller, Gregory M., Liu, Peigui, Yu, Fuqiang & Senanayake, Indunil C., 2025, A subgeneric revision of the genus Suillus (Suillaceae, Boletales) and novel taxa from Eastern Asia based on morphology and multigene phylogenies, IMA Fungus 16, pp. e 144260-e 144260 : e144260-

Suillus phylolaricinus R. Zhang, X. F. Shi, G. M. Mueller & P. G. Liu sp. nov.

Figs 28 , 29

Etymology.

“ Laricinus ” indicates that the host of this species is Larix . “ Phylo -” means this species is first discovered and confirmed by molecular phylogeny.

Typification.

China: • Yunnan Province, Diqing Tibetan Autonomous Prefecture, Shangri-la, near Tian-chi (27°34'42.45"N, 99°45'58.92"E, alt. 3321 m), 17 September 2010, Xiaofei Shi, Shi 696 (holotype HKAS 63176 ) .

Diagnosis.

The distinctive feature of S. phylolaricinus is the color change of the context at the stipe apex. When cut, the context of the upper stipe turns to greenish blue immediately.

GenBank.

ITS = KU 721438 ; LSU = KU 663211 ; TEFα- 1 = KU 721693 ; RPB 1 = KU 852243 ; RPB 2 = KU 852332 .

Morphology.

Pileus develops from convex to applanate, 3–10 cm diameter, surface viscid to glutinous, glabrous, some appressed brown scales (7 D 3–7 D 5) underneath the glue, denser in cap margin, cap usually a mixture of color patches from pale orange (6 A 2, 6 A 3) to orange brown (6 B 3, 6 C 3), younger sporophores brownish gray with olive tinge (4 C 2, 4 B 3). Pellicle is easily separable. Margin appendiculated with veil remnants and incurved slightly. Hymenophore subdecurrent to decurrent, younger ones yellowish (3 A 3, 3 A 4), turning to brownish or orange gray with age (6 B 2, 6 B 3, 6 C 2), changing to darker brownish gray when bruised. Pores 1–2 per mm, angular, compound. Tubes 4–7 mm deep. Stipe 4–10 × 0.6–2 cm, equal to slightly clavate, solid, lacking glandular dots, veil superior dry and floccose, color white turning blackish brown with age, reticulate above the annulus. Context white to yellowish (3 A 2, 3 A 3) in pileus and stipe, more yellowish at stipe apex, upper part of the stipe turning greenish blue (25 A 4, 26 A 3) when exposed, and stipe base more orange color (5 A 4). Spore print dark brown (6 F 3) when moist, dull cinnamon (6 E 6, 6 D 5) when dry. Odor and taste indistinctive.

Basidiospores [80 / 2 / 2] 7.8–11.5 × 5.0–5.5 μm, Q = (1.90) 2.00–2.30, Q sd = 2.13 ± 0.11, smooth, oblong in face view, narrowly inequilateral with a hilar appendage in profile view, hyaline yellow or brown in KOH. Basidia 2 - to 4 - spored, clavate, bulbous top, 17.0–32.0 × 5.0–10.0 μm, hyaline yellow in KOH. Hymenophoral trama not wrinkled, smooth, more or less interwoven, most 3–7 μm, up to 14 μm, thin-walled, hyaline. Pleuro- and Cheilocystidia in fascicles, abundant, clavate or cylindrical, up to 100 μm long, content brown or hyaline, surrounded by brown amorphous materials in KOH. Caulocystidia not seen. Pileipellis a layer of scales on top, hyphae smooth, content ochraceous, mostly 3–8 μm, up to 10 μm. Encrusted hyphae with hyaline granules, 3–8 μm underneath a gelatinous layer. Stipitipellis a somewhat gelatinous layer, encrusted with ochraceous amorphous materials. Context trama hyaline, smooth, thin-walled, interwoven, mostly 6–30 μm, up to 60 μm. Clamp connections absent.

Habitat.

Solitary to scattered, in high elevation forests of Larix potaninii .

Known distribution.

Currently only known from subalpine region in southwestern China.

Specimens examined.

China: • Yunnan Province, Diqing Tibetan Autonomous Prefecture, Ben Zi Lan, valley of Bai Ma Snow Mountain (alt. 4200 m), 6 September 2009, Xiaofei Shi, Shi 260 ( HKAS 63132 ) ; ibid 12 October 2011, Xiaofei Shi, Shi 1024 ( HKAS 71997 ) ; China: • Yunnan Province, Diqing Tibetan Autonomous Prefecture, Shangri-la, near Napa (27°52'48.61"N, 99°37'04.03"E, alt. 3500 m), 11 October 2011, Xiaofei Shi, Shi 1022 ( HKAS 71995 ) ; China: • Yunnan Province, Diqing Tibetan Autonomous Prefecture, Deqin Town , 18 August 2008, Yan-chun Li, Yan-chun 1518 ( HKAS 56358 ) ; China: • Tibetan Autonomous Prefecture, by the road about 24 km away from Bomi to Motuo county , 22 June 2009, Bang Feng, Bang-Feng 366 ( HKAS 57095 ) .

Notes.

Suillus phylolaricinus , S. grisellus and S. lariciphilus have appressed scales, which is a distinct morphological character in subg. Larigni . The host is another key to identify these species. Hosts of S. lariciphilus are Larix griffithiana and L. himalaica , while Larix laricina is the host for S. grisellus ( Pomerleau and Smith 1962; Adamčík et al. 2015). Suillus grisellus reported from China for the first time associated with Larix laricina .

Figures

Figure 28. Basidiomata of Suillus phylolaricinus (holotype, HKAS 63176). Scale bar: 5 cm.

Figure 29. Suillus phylolaricinus (holotype, HKAS 63176). a Basidiospores; b Cheilocystidia; c Hymenium with basidia; d Pileipellis (mature specimens). Scale bar: 5 μm (a); 20 μm (b – d).