Clavariadelphus amplus J. Zhao, L.P. Tang & Z.W. Ge, 2020

Huang, Hong-Yan, Zhao, Jie, Zhang, Ping, Ge, Zai-Wei, Li, Xian & Tang, Li-Ping, 2020, The genus Clavariadelphus (Clavariadelphaceae, Gomphales) in China, MycoKeys 70, pp. 89-121 : 89

publication ID	https://dx.doi.org/10.3897/mycokeys.70.54149
persistent identifier	https://treatment.plazi.org/id/7E4AB4F0-C743-5038-9598-D8BEEFF384DC
treatment provided by	MycoKeys by Pensoft
scientific name	Clavariadelphus amplus J. Zhao, L.P. Tang & Z.W. Ge
status	sp. nov.

Treatment

2. Clavariadelphus amplus J. Zhao, L.P. Tang & Z.W. Ge sp. nov. Figs 2b, c View Figure 2 , 3b View Figure 3 , 4b View Figure 4 , 5b View Figure 5 , 7a, b. View Figure 7

Diagnosis.

This species is unique in its pink-orange basidiomes with enlarged, truncate and sterile apices, ellipsoid basidiospores, hyphae of the basal mycelium with nipple-shaped protuberances and prism-like crystals and basidiomes turning cherry-red in KOH. It differs from C. truncatus by the latter’s darker coloured basidiomes, narrower apices and larger basidiospores.

Etymology.

Latin " amplus " refers to the enlargement of the apex of the basidiomes.

Description.

Basidiomes up to 15 cm high, 0.5-1 cm diam. at the base, enlarged upwards to 3-7.5 cm diam. near apex; hymenium initially smooth, longitudinally rugulose in age, pruinose, pinkish-orange (7A5-7), paler downwards, greyish-orange (5B4-5); apex initially obtuse or broadly rounded, finally truncate, depressed, surface rugose to rugulose, more or less darker than the hymenium, apricot-yellow (5B6-7) to pink-orange, reddish-orange (7A7-8) or red-orange (7B7-8) at maturity; surface slowly staining light brown or light leather-brown (7D6-7) to brown (7E6-7) when cut or bruised, staining more conspicuously downwards; base simple, terete, nearly smooth, cylindrical to subcylindrical, pruinose; mycelial hyphae interwoven, white; flesh solid initially, then soft and spongy upwards as the apex enlarges, white, slowly staining light leather-brown (7D6-7) to brown (7E6-7) on exposure. Odour pleasant. Taste not distinctive. Spore deposit not recorded.

Hymenium limited to the sides of basidiomes, composed of basidia and leptocystidia; the apex of basidiomata is composed of sterile elements 18-28 × 5-8 μm, clavate, thin-walled, smooth, clamped. Basidia 85-95 × 8-12 μm, clavate, hyaline, thin-walled, (2-) 4-spored, sterigmata 9-11 μm in length. Basidiospores [40/2/2] 8.2-11.0 × 5.1-6.4 μm, Q = (1.36-) 1.38-2.00 (-2.18), Q m = 1.75 ± 0.17, ellipsoid to broadly ellipsoid, ovate or amygdaliform, with a small apiculus, inamyloid, thin-walled, hyaline in KOH, smooth. Leptocystidia 45-70 × 2.8-3.8 μm, scattered amongst and scarcely projecting beyond the basidia, cylindrical to narrowly clavate, thin-walled, smooth, hyaline, non-pigmented, clamped, inflated apically at maturity and at times, with apical or subapical branches. Mycelial hyphae 2-4 μm diam., parallel, interwoven or aggregated into rhizomorphic strands, branched, clamped; walls thin or irregularly slightly thickened, the hyphal walls echinulate with light microscopy, covered with nipple-shaped protuberances, as well as encrusted with prism-like crystals (up to 6 μm long) that are insoluble in KOH.

Chemical reactions.

(dried basidiomes): FeCl3 = positive, green-yellow; KOH = positive, cherry-red or pink; NH4OH = positive, golden-rod or vivid yellow; phenol = positive, light yellow; ethanol, FeSO4, and Melzer’s reagent = negative.

Known distribution and ecology.

NW China and SW China, and India. Gregarious habit on the ground in conifer or mixed conifer forests (e.g. Abies spp. and Picea spp.) at elevations ranging from 3000-3950 m.

Materials examined.

China. Gansu Province: Zhouqu Prefecture, under Abies spp., 6 August 2005, X.T. Zhu 728 (HKAS 76577). Qinghai Province: Qilian mountains, 38°6.00'N, 100°7.03'E, alt. 3000 m, 21 August 2004, H.A Wen 4305 (HMAS 132008); same location and date, Q.B. Wang 438 (HMAS 97090). Sichuan Province: Seda Prefecture, Picea - Juniperus forests, 31°43.20'N, 100°43.17'E, alt. 3775-3925 m, 6 August 2005, Z.W. Ge 783 (HKAS 49278); Litang Prefecture, 5 August 2007, Z.W. Ge 1712 (HKAS 53797). Tibet: Linzhi City, 29°20.07'N, 094°18.00'E, alt. 3850 m, 19 July 2004, Y.H. Wang 125 (HMAS 97248); Jilong Prefecture, on the ground in coniferous woods, 12 September 1990, J.Y. Zhuang 3814 (HMAS 59867); Chengdu City, under forests dominated by Picea spp., 31°30.43'N, 097°20.07'E, alt. 3480-3550 m, 17 August 2004, Z.W. Ge 381 (HKAS 46160); Riwoqe Prefecture, under Picea spp., 31°14.27'N, 096°31.92'E, alt. 3890 m, 12 August 2004, Z.W. Ge 340 (HKAS 46120). Yunnan Province: Shangri-La Prefecture, Haba Snow Mountains, alt. 2800 m, 15 August 2008, L.P. Tang 645 (HKAS 54876, Holotype); Shangri-La Prefecture, 27°28.13'N, 099°25.03'E, alt. 3600 m, 15 August 2008, T.Z. Wei 172 (HMAS 250466).

Comments.

Clavariadelphus amplus is distinctive by its pink-orange to red-orange, bright basidiomes, obviously enlarged, truncate, depressed, sterile apices (up to 7.5 m diam.) at maturity, large basidiospores (8.2-11.0 × 5.1-6.4 μm), gregarious habit at high elevations, base mycelial hyphae with nipple-shaped protuberances and prism-like crystals and a cherry-red staining reaction to KOH. It is sold as an edible mushroom in markets in SW China. This taxon has a wide distribution in NW and SW China, including Gansu, Qinghai, Sichuan, Tibet and Yunnan Provinces. The data from GenBank (accession MT012805) also indicated its distribution of India.

This species was previously referred to as either C. pallido-incarnatus ( Yuan and Sun 1995) or C. truncatus ( Mao et al., 1993; Zang 1996; Mao 2009; Tang and Yang 2014; Tang 2015). Clavariadelphus pallido-incarnatus , a species described from the Pacific Northwest in North America, has pale pinkish-cinnamon basidiomes with fertile, non-truncated apices, no reactivity to KOH and habitat preference for coastal forests of Sequoia sempervirens and Picea sitchensis ( Methven 1990). Clavariadelphus truncatus from Europe is readily confused with C. amplus as they have similar size and truncate sterile apex. However, C. truncatus has dark coloured basidiomes from yellow to cinnamon-brown or brown, narrower apices (up to 3.5 cm) and larger basidiospores (10.3-12.6 × 5.5-7.1 μm from neotype; Methven 1990). Clavariadelphus unicolor (Berk. & Ravenel) Corner, is also from North America and has enlarged sterile apices, but it is distinct in its reddish-brown to violet-brown basidiomes, narrow basidiospores with Q m 2.1, a golden-yellow reaction to KOH and association with deciduous trees ( Methven 1990).

So far, there are two species with sterile apices found in China, C. amplus and C. gansuensis . However, C. gansuensis has a narrower apex (up 1.6 cm), slightly broader basidiospores with a lower Q value (8.3-10.1 × 5.3-6.3 μm, Q = 1.47 -1.78, Q m = 1.60) and a solitary growth habit. Except for the mentioned species, C. amplus is also similar to C. pakistanicus . Clavariadelphus pakistanicus , another species also from Asia, is distinct in smaller basidiomes (up to 12 cm high), with narrower fertile apices (up to 1.4 cm), smaller basidiospores (7.5-9.2 × 4.0-5.6 μm), solitary growth habit at lower elevations and violet-brown staining reactions to KOH ( Hanif et al. 2014).

In the ITS tree, C. amplus exhibits a sister relationship with C. pakistanicus with strong support (Fig. 1 View Figure 1 ).