Phaeoclavulina yunnanensis W. H. Lu., D. G. Zheng., Karun. & Tibpromma. 2024, sp. nov.

Phaeoclavulina yunnanensis W.H. Lu., D.G. Zheng., Karun. & Tibpromma., sp. nov. FIGURE 2 Index Fungorum number: IF 902645 Etymology: “Yunnanensis ” refers to Yunnan Province where the holotype was first collected. Holotype: HKAS 127150 Basidiomata medium, (28–) 30–60 (–63) × (9–) 10–20 (–21) mm, humicolous, gregarious to solitary, erect, the overall appearance is cylindrical and coral-shaped, yellow, fleshy, and sticky when fresh, and orange-yellow (4 A 8) to light orange (5 A 5) when dry. Stipe 8–40 (–41) mm high, gradually narrowing, forming a unique funicular rhizome, widening toward branching, a few connected transversely to adjacent stalks, with deep grooves at junctions of fused branches, smooth, glabrous, and reddish yellow (4 A 6–7) to light yellow (4 A 4) rhizomorph white; Base part light yellow (2 A 5), context pithy to hollow, sticky, watery fluid exudes when broken, stiff and waxy after drying, and the bruise is unaltered. Branches 4–5 ranks, ascending, polychotomous, gelatinous, and smooth from the outside, pale orange; axils roughly rounded; apices 2–4 mm long, blunt to sharp, and pale orange (5 A 3) up to the tips with a little greenish-grey (27D2) tint. Odour not distinctive. Basidiospores (3–) 4–6 × 2–3.5 (–4) μm [Q =1.5–2.43, Q m =1.98 ± 0.21], oblong to ellipsoid, slightly bent at end, faintly cyanophilic contents, somewhat thick wall; verrucose, multi-guttulate when mature, with roughened form of low, coarse warts and delicate, meandering ridges. Basidia (18–) 20–40 (–45) × 3–5 (–6) μm, clavate, clamped; contents homogeneous when young, slightly grainy, hyaline or slightly yellowish, slightly cyanophilous, 4-spored. Hyphal system septate, branching, agglutinated with crystalline contents, monomitic, and with septate generative hyphae; tramal hyphae of branches (1.8) 2–5 μm wide, narrow to thick-walled, branching, parallel, and compactly organized. Clamp connections are present. Habitat: Gregarious on the soil around Quercus sp. Distribution: Only known from Yunnan, China. Material examined: China, Yunnan Province, Qujing Normal University, on soil under a Quercus sp., 25°31′08′′ N 103°45′27′′ E, elev. 1,625 m, 14 June 2022, W. Lu, QJ128 (HKAS 127150, holotype). Additional specimens examined: China, Yunnan Province, Qujing Normal University, on soil under a Quercus sp., 25°31′11′′ N 103°45′5′′ E, elev. 1,628 m, 14 June 2022, W. Lu & S. C. Karunarathna, QJ342 (HKAS 128154, paratype). Notes: In phylogenetic analyses (Figure 1), our new collections of P. yunnanensis were well-separated from P. carovinacea specimens (AMB 18533, AMB 18534, AMB 18551, TUR-A-209584) with 58% BS and 0.95 PP statistical support. Morphologically, P. yunnanensis differs from P. carovinacea by having smaller basidiomata (30–60 × 10–20 mm vs. 50–70 × 20–30 mm), longer stipe (8–40 vs. 30 mm), connections of branches are reddish yellow to light yellow, base part light yellow, smaller basidia (20–40 × 3–5 mm vs. 28–40 × 5–7 mm), and narrower hyphae branches (2–5 μm vs. 8–10 μm). In addition, P. yunnanensis is similar to P. jilinensis which was reported in China (MHHNU 10504) (Deng et al. 2024). Phaeoclavulina yunnanensis differs from P. jilinensis by having reddish-yellow to light yellow, smaller basidiomata (30–60 × 10–20 mm vs. 35–90 × 15–50 mm), verrucose, smaller basidiospores (4–6 × 2–3.5 μm vs. 6–8 × 3–5 μm), polychotomous, blunt sharp spines, smooth and gelatinous at the top of branches (Deng et al. 2024). However, the phylogenetic analysis indicates that P. yunnanensis and P. jilinensis are clustered in different clades (Figure 1). Therefore, in this study, P. yunnanensis is introduced as a new species based on morphological and molecular evidence.