Amoenoboletus brachysporus (Boletaceae), a new species from Southern China Li, Ting Zhong, Guorui Li, Taihui Deng, Wangqiu Zhang, Ming Phytotaxa 2024 2024-01-03 633 1 51 59 Ming Zhang, T. Li & T.H. Li Ming Zhang, T. Li & T. H. Li 2024 [136,810,1652,1680] Agaricomycetes Boletaceae Amoenoboletus CoL,GBIF Fungi Boletales 3 54 Basidiomycota species brachysporus sp. nov.   Diagnosis: Distinguished from other  Amoenoboletusspeciesby the combination characters of the larger basidiomata (pileus up to 8.5 cmbroad), pale yellow pileus surface covered with yellowish brown to reddish brown appressed squamules, red to dark red stipe surface with dense, coarse, fibrillose-appressed belts or squamules, and the shorter basidiospores.  Etymology: The epithet “ brachy-” means short, “- sporus” means spores, “ brachysporus” refers to the new species with shorter basidiospores    Holotype: CHINA. Guangdong province, Guangzhou, Baiyun Mountain, at 23°11′ N, 113°17′ E, alt.  100 m,  17 June 2021, coll.  Ming Zhang( GDGM85730!).  Description: Basidiomatamedium to large sized. Pileus 4–8.5 cmbroad, subhemispherical to convex when young, expanding to plano-convex to applanate in age; background colour pale yellow, covered with greyish yellow, yellowish brown to reddish brown (3B5–5E 5, 4E6–5E 6, 9E5–9E8), conspicuous patches or coarse fibrillose-appressed squamules, cracked from centre to margin; margin slightly uplifted in age; surface dry. Context 0.6–1 cmthick at the centre of pileus, yellowish white to pale yellow (2A2–3A2, 2A3–3A3), unchanging upon bruising. Tubes 0.4–0.6 cmdeep, depressed around stipe, pastel yellow to greyish yellow (1A4–2A4, 1B4–2B4) in age, unchanging when bruised; Poresangular, 1–2 per mm, orange red, greyish red to red (8A7–11A7, 8B5–10B5) when young, gradually fading from pastel red to greyish yellow (8A3, 4B5) in age, unchanging or slightly bluish white (22A2) when bruised. Stipe4–9 × 1.2–2.2 cm, central, subcylindrical or clavate, solid, equal or slightly enlarged downwards, background concolorous with the pileal context, surface densely covered with red to vivid red (9A7–11A7) granular-punctate, fibrillose-appressed belts or coarse squamules, unchanging when bruised or in age; pale yellow (2A2–3A2) at base; basal mycelium white to yellowish white (1A2). Stipe context yellowish white to pale yellow (2A2–3A2, 2A3–3A3), unchanging or slightly bluish white (22A2) upon exposure. Odourindistinct. Tastemild.   FIGURE 2.Basidiomata of  Amoenoboletus brachysporus. a–c, e: GDGM 85730 (holotype); d: GDGM 87379; f–h: GDGM 92249. Bars: a, b = 50 mm; c, e = 20 mm; d, f–h = 10 mm. Photographed by Ming Zhang and Guorui Zhong.  Basidiospores[80/5/3] (7–)7.5–8.5(–9) × (5–)5.5–6(–6.3) μm, Q = (1.17–)1.3–1.41(–1.5), Q m= 1.35±0.09, broadly ellipsoid to ellipsoid, barely inequilateral in profile, smooth, greyish yellow to butter yellow (2B5–4B5) in 5% KOH, inamyloid, thin-walled. Basidia27–38 × 10–13 μm, clavate, hyaline and containing scattered straw-yellow (3B4) oil guttules in 5% KOH and light yellow (4A4) in Melzer’s reagent, inamyloid, 4-spored, sterigmata 3–6 μm long, basal clamps absent. Cheilocystidia18–30 × 6–13 μm, sparse, fusiform, thin-walled, yellowish white (1A2) to nearly hyaline in 5% KOH. Pleurocystidia45–58(–63) × 6–12 μm, sparse, irregularly cylindrical or cylindrical-fusiform, on average usually slightly narrower than cheilocystidia, colour and chemical reactions similar to cheilocystidia. Hymenophoral tramasubparallel to somewhat bilateral, yellowish (1A2) to hyaline in 5 % KOH, light yellow (4A4) in Melzer’s reagent, composed of 4–8 μm wide branching hyphae, yellowish (1A2) to hyaline in 5 % KOH, yellowish brown in Melzer’s reagent, thin-walled. Pileipellismade up of loosely entangled hyphae, occasionally branched, smooth, thin-walled, hyaline, sometimes outer surface covered with brown granular pigment. Stipitipelliscomposed of broadly clavate inflated hyphae 10–30 × 6–10 μm, pale yellow (1A3) to hyaline in 5 % KOH. Caulocystidia15–28 × 6–12 μm, cylindrical or cylindrical-fusiform, thin-walled. Stipe tramacomposed of longitudinally arranged cylindrical hyphae 4–12 μm wide, thin-walled, branched, smooth, yellowish white (1A2) to hyaline. Clamp connectionsabsent.   FIGURE 3.Microscopic features of  Amoenoboletus brachysporus(GDGM 85730, holotype). a. Basidiospores b. Basidium with basidioles. Bars: a, b = 10 μm. Photographed by Ting Li.   FIGURE 4.Microscopic features of  Amoenoboletus brachysporus(GDGM 85730, holotype). a. Basidiospores b. Pileipellis. c. Pleurocystidia d. Cheilocystidia. e Stipitipellis with caulocystidia. Bars = 10 μm. Line drawings by Ting Li.  Known distribution: Currently only known from Guangdong province, Southern China.  Habit and habitat: Solitary to scattered on soil in broadleaf forest mainly dominated by Fagaceaetrees, and mixed with other broadleaf trees as  Acacia auriculiformisA. Cunn. ex Benth.,  Schima superbaGardner & Champ.  Additional specimens examined:  CHINA. Guangdong province, Guangzhou,  Baiyun National ForestPark, at 23°11′ N, 113°17′ E, alt.  155 m,  21 June 2021, coll.  Xiaoqing Huang GDGM 87379;  Guangzhou,  Baiyun National ForestPark, at 23°11′ N, 113°17′ E, alt.  132 m,  7 July 2023, coll.  Guorui Zhong GDGM 92249. 2021-06-17 GDGM Ming Zhang China 100 23.183332 Baiyun Mountain 1256 113.28333 Guangzhou 3 54 GDGM85730 1 Guangdong holotype 2021-06-21 GDGM Xiaoqing Huang China Guangzhou 155 23.183332 Baiyun National Forest 1256 113.28333 Baiyun National Forest Park 6 57 GDGM 87379 1 Guangdong 2023-07-07 GDGM Guorui Zhong China Guangzhou 132 23.183332 Baiyun National Forest 1256 113.28333 Baiyun National Forest Park 6 57 GDGM 92249 1