Suillus pinetorum (W. F. Chiu) H. Engel & Klofac

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 pinetorum (W. F. Chiu) H. Engel & Klofac , in Engel, et al., Schmier- und Filzröhrlinge s. l. in Europa, Die Gattungen Boletellus, Boletinus, Phylloporus, Suillus, Xerocomus (Weidhausen b. Coburg): 12 (1996)

Figs 26 , 27

Basionym.

Boletinus punctatipes var. pinetorum W. F. Chiu Mycologia, 40 (2): 200 (1948)

Holotype.

China: • Yunnan Province, Kunming, Tiehfungan , 12 November 1941, W. F. Chiu (no. 7717)

Diagnosis.

Suillus pinetorum is morphologically identical to S. bovinus . This species is in association with Pinus yunnanensis and P. massoniana in southwestern China.

Typification.

China: • Yunnan Province, Kunming City, Dong Zhan, Qinglong Village (25°03'13.70"N, 102°48'1.50"E, alt. 1942 m), 15 August 2012, Rui Zhang, RZ 08151203 (neotype designated here, HKAS 91427 , MBT 10025711 ) .

Morphology.

Pileus develops from convex to flat, margin inrolled at first, then expanding, 3–5 cm diameter, up to 8 cm broad, surface dry or viscid in moist, glabrous, color beige (5 A 3) to ochraceous cinnamon (5 A 6, 5 B 6). Pellicle peeling off easily. Hymenophore subdecurrent to decurrent, younger ones ochraceous (5 B 4), turn to darker ochraceous (5 B 5, 5 C 5) with age. Pores 1–1.2 mm diameter, angular, compound, radially arranged or inconspicuously lamellate. Tubes 1–4 mm deep, concolorous with pores, dotted with cinnamon (6 A 4) colored glandular dots. Stipe 3–4 × 0.3–1.5 cm, tapering downwards, solid, no glandular dots, no ring, concolorous with pileus, covered with some cinnamon or pinkish (5 C 6) small streaks. Context yellowish white to light orange (5 A 2) in both pileus and stipe, more pinkish (6 A 2) near cuticles. Do not change color anywhere. Mycelia white. Spore print olive brown (4 D 3). Odor and taste pleasant, chewy texture.

Basidiospores [80 / 2 / 4] (7.0) 7.5–8.5 × 3.0–3.5 μm, Q = (2.00) 2.14–2.67, Q sd = 2.33 ± 0.14, smooth, oblong in face view, narrowly inequilateral with a hilar appendage in profile view, hyaline yellowish in KOH, tawny brown in Melzer’s. Basidia 4 - spored, clavate, bulbous top, 25.0–30.0 × 6.5–8.5 μm, hyaline yellow in KOH. Hymenophoral trama divergent, all encrusted by fine granules, thin-walled, smooth to wrinkled, mostly 4–8 μm. Pleuro- and Cheilocystidia in fascicles, abundant, clavate or cylindrical, up to 70 μm long, content brown or hyaline, surrounded by brown amorphous materials in KOH. Caulocystidia not seen. Pileipellis an ixocutis, hyphae hyaline, thin-walled and encrusted with hyaline to ochraceous granules, scattered in glue, mostly 3–8 μm, up to 14 μm wide. Stipitipellis encrusted by patches of amorphous pigments, most hyphae thin-walled, septated, interwoven, up to 13 μm wide. Context trama hyaline, smooth, thin-walled, interwoven, similar for pileus and stipe, mostly 4–20 μm, widest at stipe base to 40 μm. Clamp connections absent.

Habitat.

Solitary to scattered, in association with Pinus yunnanensis and P. massoniana .

Known distribution.

Mainly distributed 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 ) ; China: • Yunnan Province, Zhanyi Town, Zhu Jiang Yuan, Maxiong Mountain , 30 June 2008, Xiaofei Shi, Shi 120 ( HKAS 63281 ) ; China: • Yunnan Province, Dehong Prefecture, Yingjiang, from Tongbi Guan to Xima about 12 km , 18 July 2009, Yanchun Li, Yanchun-Li 678 ( HKAS 59425 ) ; China: • Guizhou Province, Zunyi City, from Daozhen to Yangxi about 3 km (alt. 1120 m), 28 July 2010, Xiaofei Shi, Shi 393 ( HKAS 63200 ) ; China: • Guizhou Province, Guiyang City, Kaiyang Town, Yonggang village, Gangzhai plantation (alt. 1300 m), 19 June 2010, Xiaofei Shi, Shi 348 ( HKAS 63136 ) , China: • Hunan Province, Zhang Jia Jie City, Zhang Jia Jie National Forest Park , 16 June 2010, Xiaofei Shi, Shi 344 ( HKAS 63137 ) .

Notes.

Suillus pinetorum was first documented as “ Boletinus punctatipes var. pinetorum ” by Chiu (1948) and later illustrated by Chiu (1957). The illustration, host and most part of the morphological descriptions match with our collections. However, not as Chiu (1948, 1957) described, the species does not have brown glandular dots and morphological descriptions of this species could be enriched with more details. In addition, the affiliation of Suillus pinetorum under Boletinus punctatipes is remotely correct, whereas comparisons with S. bovinus were missing. ( Engel et al. 1996) reclassified the variety by Chiu (1948) under genus Suillus and raised its taxonomic level to species. The type collected by Chiu (1948) is missing at the fungarium of the Institute of Microbiology, Academia Sinica in Beijing, China; so a neotype is assigned here.

Suillus pinetorum is morphologically identical with S. bovinus . Suillus bovinus associates with Pinus sylvestris and distributes from Europe to northeastern China. Suillus pinetorum under current delimitation seems to contain new cryptic species. Collections associated with Pinus yunnanensis in southwestern China are not phylogenetically the same as collections growing with Pinus massoniana in southwestern and central China. It is uncertain if host association is rigorous for delimiting cryptic species. Pinus yunnanensis and P. massoniana are not sister species, and geographic ranges of the two overlap in southwestern China.

Figures

Figure 26. Basidiomata of Suillus pinetorum (neotype, HKAS 91427). Scale bar: 5 cm.

Figure 27. Suillus pinetorum (neotype, HKAS 91427). a Basidiospores; b Cheilocystidia; c Hymenium with basidia; d Pileipellis (mature specimens). Scale bars: 5 μm (a); 20 μm (b – d).