Rickenella danxiashanensis Ming Zhang & T.H. Li, 2018

Rickenella danxiashanensis Ming Zhang & T.H. Li , sp. nov. Fig. 2 View FIGURE 2

Mycobank: MB 821625

Etymology: The specific epithet danxiashanensis refers to the type locality of Danxiashan National Nature Reserve in Guangdong province of China.

Diagnosis: Differs from R. fibula in having a larger basidiomata and larger basidiospores 4–6 × 3–4 μm.

Type:— CHINA. Guangdong Province, Shaoguan City, Yinhua Town, Danxiashan National Nature Reserve , on moss, alt. 150 m, 113°45 ′E, 25°03 ′N, 17 Sep 2015, Ming Zhang ( GDGM45529 holotype!) GoogleMaps

Macroscopic characters:—Basidiomata small, omphalinoid ( Fig. 2 View FIGURE 2 ). Pileus 3–17 mm wide, hemispheric at first, becoming convex to nearly plane with a shallow central depression and slightly wavy margin in age, surface dry to hygrophanous, smooth with faintly pellucid-striate toward margin, yellow, yellowish orange, orange to deep orange (2A7–6A7) at massive, deep orange to reddish orange (4A8–7A8) at the center. Lamellae 12–15 in girth, decurrent to deeply decurrent, furcate or transvenose, white to yellowish white, up to 2 mm wide; 2–3 lamellulae of different lengths between the two complete lamellae, edge entire, concolorous, intervenose, not or occasionally forked. Stipe 5– 20 × 0.5–2 mm, central, cylindrical to subcylindrical, often curved, equal or slightly tapered downwards, cartilaginous, solid, white to yellowish white, somewhat translucent, surface covered with finely pubescent, basal mycelia white. Odor and taste not distinctive.

Microscopic characters:—Baisdiospores [90/6/6] (3.5–)4–6 × (2.5–)3–3.5 μm, Q = (1.43)1.51–1.82(–2.0), Qm = 1.63 ± 0.21, ellipsoid, thin-walled, hyaline, smooth, inamyloid. Basidia 15–27 × 4–6 μm, clavate, 2, 4-spored, thin-walled; sterigmata 2–3.5 μm, often clamp connections at the bases of basidia. Pleurocystidia 34–43 × 7–10 μm, narrowly lageniform to sub-capitate, often with subcapitate apex, hyaline, thin-walled, inamyloid. Cheilocystidia similar to pleurocystidia in shape and size. Lamella trama subregular, hyphae 5–15 μm wide, cylindrical or subfusoid, thin-walled, hyaline, inamyloid. Pileus trama subregular, hyphae 3–12 μm wide, with cylindrical or subfusoid elements, thin-walled, hyaline, inamyloid. Pileipellis a cutis with scattered pileocystidia, hyphae 5–12 μm wide, cylindrical or subfusoid, thin-walled, hyaline. Pileocystidia 40–75 × 7–13 μm, narrowly lageniform to obclavate, often with subcapitate apex, hyaline, thin-walled. Stipitipellis a cutis with scattered caulocystidia, hyphae 3–11 μm wide, with cylindrical elements, hyaline, thin-walled. Caulocystidia 35–55 × 7–10 μm, narrowly lageniform to obclavate, often with subcapitate apex, hyaline, thin-walled. Clamp connections present.

Habit, habitat and distribution:—Scattered or in small groups on moss bed mainly consists of Bryum argenteum Hedw. , Campylopus flexuosus (Hedw.) Brid and Polytrichum commune L.ex Hedw. alt. 150–280 m; only known from the type locality in southern China.

Additional materials examined:— CHINA. Guangdong Province, Shaoguan City, Yinhua Town, Danxiashan National Nature Reserve , on moss, alt. 150 m, 113°45 ′E, 25°03 ′N, 17 Sep 2016, Zong-Ping Song ( GDGM45576 ) GoogleMaps ; same locality, 18 Sep. 2016, Tai-Hui Li ( GDGM45513 ) GoogleMaps ; Ming Zhang ( GDGM45679 ) GoogleMaps ; same locality, 23 April 2017, Tai-Hui Li ( GDGM48169 ) GoogleMaps ; same locality, 23 April 2017, Huang Hao ( GDGM48302 ) GoogleMaps