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

Figs 22 , 23

Etymology.

The cap color of this species is cinnamon.

Diagnosis.

Suillus subcinnamomeus has cinnamon color pileus and ivory white glandular dots when young. This species is in association with Pinus pumila in northeastern China.

Typification.

China: • Heilongjiang Province, Da Xing Anling, Dabai Mountain (alt. 1000 m), 22 August 2010, Xiaofei Shi, Shi 601 (holotype, HKAS 63222 ) .

GenBank.

ITS = KU 721496 .

Morphology.

Pileus convex or obtuse, 4–7 cm diameter, surface viscid to glutinous, glabrous, background color yellow (4 A 6) or light cinnamon (5 A 5), small color streaks of bright reddish cinnamon (6 A 7, 6 A 8) resemble fibrils covering all over the cap. Hymenophore adnate, younger ones dark cinnamon (6 D 3–6 D 5), become more olive brown (5 E 5,5E 6) with age. Do not change color when bruised. Pores 2 per mm, round or angular. Tubes 3–6 mm deep, concolorous with pores. Stipe 6.5–8.5 × 1.2–1.8 cm, bulbous at base or clavate, solid, concolorous with pileus, with more reddish brown or cinnamon (5 E 6 or 6 C 7) color streaks. Glandular dots all over, ivory white (5 A 1) when young, become reddish brown (5 E 6) or brown (5 F 6) with age. Mycelia pinkish (6 A 5, 6 A 6) Context white to yellowish in pileus and stipe, light cinnamon (5 A 2, 5 A 3) close to the cuticles. Do not change color when exposed. Spore print unknown. Odor and taste indistinctive.

Basidiospores [40 / 2 / 2] 8.5–10.0 (10.5) × 3.5–4.5 μm, Q = 2.13–2.57, Q sd = 2.34 ± 0.13, smooth, oblong in face view, narrowly inequilateral with a hilar appendage in profile view, hyaline to yellowish in KOH, tawny yellow in Melzer’s. Basidia 4 - spored, clavate, bulbous top, 23.0–32.0 × 6.2–7.5 μm, hyaline to yellowish in KOH, tawny yellow in Melzer’s. Hymenophoral trama divergent, thin-walled, very wrinkled, encrusted with some ochraceous granules in KOH, usually 6–8 μm. Pleuro- and Cheilocystidia abundant, in fascicles, clavate, up to 70 μm long, content brown or hyaline, surrounded by brown amorphous materials in KOH. Caulocystidia similar with pleuro- and cheilocystidia, septated once or twice especially at the base. Pileipellis a layer of scattered hyphae in glue, densely encrusted with fuzzy appearance and surrounded by tiny brown granules in KOH, most hyphae 5–7 μm, up to 8.5 μm wide. Stipitipellis a thick layer of brown amorphous pigments covers the stipe, with abundant caulocystidia intruding outwards. Context trama hyaline, smooth, thin-walled and interwoven, similar for pileus and stipe, mostly 22–32 μm, widest at stipe base to 43 μm. Clamp connections absent.

Habitat.

Solitary, associated with Pinus pumila .

Known distribution.

In northeastern China.

Specimens examined.

China: • Heilongjiang Province, Da Xing Anling, Xinlin Yuanlin Yuan park (alt. 600 m), 27 August 2010, Xiaofei Shi, Shi 615 ( HKAS 63240 ) .

Notes.

This species is morphologically and phylogenetically very distinct. Sister species Suillus punctipes does not have such reddish cinnamon cap color and ivory white glandular dots when young.

Figures

Figure 22. Basidiomata of Suillus subcinnamomeus (holotype, HKAS 63222) Scale bar: 5 cm.

Figure 23. Suillus subcinnamomeus (holotype, HKAS 63222). a Basidiospores; b Cheilocystidia; c Hymenium with basidia; d Pileipellis (mature specimens). Scale bars: 5 μm (a); 20 μm (b – d).