Sarcodon coactus Y.H. Mu & H.S. Yuan, 2020

Mu, Yan-Hong, Hu, Ya-Ping, Wei, Yu-Lian & Yuan, Hai-Sheng, 2020, Hydnaceous fungi of China 8. Morphological and molecular identification of three new species of Sarcodon and a new record from southwest China, MycoKeys 66, pp. 83-103 : 83

Sarcodon coactus Y.H. Mu & H.S. Yuan sp. nov. Figures 2 , 3 , 4

Diagnoses.

Differs from Sarcodon thwaitesii by slightly shorter and decurrent spines, olivaceous tissues in KOH, simple-septate hyphae in all parts of basidiocarp, narrower basidia with shorter sterigmata and smaller basidiospores.

Type.

China. Yunnan Province, Chuxiong, Zixishan Nat. Res., 24°58'28"N, 101°22'13"E, 2000 m alt., solitary to gregarious, on the ground in Fagaceae forest, 19.07.2018, Wei 8094 (holotype: IFP 019351).

Etymology.

Coactus (Lat.), refers to the felted pileal surface.

Description.

Basidiocarps annual, solitary to gregarious, soft and fleshy when fresh, becoming firm and light in weight upon drying; taste none, odour farinaceous when dry. Pileus planar, ellipsoid when young, later round with age, up to 35 mm across and 4-8 mm thick at centre. Pileal surface reddish-brown (8D5) to dark brown (8F8), azonate, pubescent, floccose to felted when fresh, becoming smooth, rugose, scrobiculate when dry; margin white (7A1) when fresh, greyish-brown (7D3) with age, incurved, rarely lobed. Spine surface white (4A1) to yellowish-white (4A2) when fresh, brownish-orange (5C5) to yellowish-brown (5F6) when dry; spines up to 2.1 mm long, base up to 0.3 mm diam., conical, 3-5 per mm, decurrent on stipe, without spines at pileus margin, brittle when dry. Context not duplex, up to 6 mm thick, light brown (5D5), firm; Stipe central, up to 5.5 cm long and 1.3 cm diam., fleshy, greyish-brown (8D3) to violet brown (10F7) when fresh, becoming hollow with age, greyish-orange (5B3) to dark brown (7F7) upon drying, rugous, columniform or attenuate below with bulbous base when old.

Hyphal structure. Hyphal system monomitic; generative hyphae with simple-septa, CB-, IKI-; tissues olivaceous in KOH.

Context. Generative hyphae hyaline, thin-walled, rarely branched, simple-septate, inflated, partly short-celled, interwoven, mostly 4-10 μm diam.

Spines. Tramal hyphae hyaline, thin-walled, frequently branched, more or less parallel along spines, frequently simple-septate, straight, 2-5 μm diam. Cystidia and cystidioles absent. Basidia clavate, thin-walled, with four sterigmata (3.1-5.2 μm long), simple-septate at base, 16.5-50 × 6.2-9.4 μm; basidioles similar to basidia.

Basidiospores irregular subglobose, brown, thin-walled, tuberculate, CB-, IKI-, (5.1-)5.7-7(-7.1) × (4.6-)4.7-5.9(-6) μm, Lm = 6.2 μm, Wm = 5.3 μm, Q = 1.17-1.18 (n = 60/2); tuberculi usually isolated or grouped in 2 or more, bi- to trifurcate-like in shape, up to 1.0 μm long.

Additional specimen examined

- China. Yunnan Province, Maguan County, On the way from Dalishu Township to Damagu Village, 23°4'55"N, 104°12'59"E, 1616 m alt., solitary, on the ground in Fagaceae forest, 7.08.2017, Shi 181 (IFP 019352).

Figures

Figure 2. A basidiocarp of Sarcodon coactus (holotype: IFP 019351).

Figure 3. SEM of basidiospores of Sarcodon coactus (holotype: IFP 019351).

Figure 4. Microscopic structures of Sarcodon coactus (drawn from IFP 019351) a basidiospores b section of hymenophoral trama with basidia c hyphae from pileal context.