Clavariadelphus gansuensis J. Zhao & L.P. Tang, 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

4. Clavariadelphus gansuensis J. Zhao & L.P. Tang sp. nov. Figs 2f , 3d , 4d , 5d , 9a, b

Diagnosis.

This species is characterised by its orange, clavate basidiomes with slightly enlarged, truncate, sterile apex, broadly ellipsoid to ellipsoid basidiospores, hyphae of the basal mycelium with nipple-shaped protuberances and prism-like crystals and basidiomes that turn pink or light cherry-red in KOH. It differs from C. truncatus by the latter’s robust, darker basidiomes with enlarged apices, and larger basidiospores.

Etymology.

Latin " gansuensis " refers to the holotype location in Gansu Province.

Description.

Basidiomes up to 9 cm high, enlarged upwards to 1.6 cm diam., simple, clavate; hymenium longitudinally rugose, pruinose, light yellow to greyish-orange at maturity; apex initially obtuse or broadly rounded, flattening laterally, then truncate, slightly rugose, light orange or melon-orange (5A5-7) to orange (6A6-7) in age; base terete, smooth, pruinose, dirty white or pallid where covered, otherwise pruinose, pale orange or light orange (5A3-4); mycelial hyphae white; flesh initially solid, then soft and spongy upwards as the apex enlarges, white to pallid. Odour and taste not recorded.

Hymenium limited to the side of basidiomata, composed of basidia and leptocystidia; the apex of basidiomata composed of sterile elements 15-25 × 5-7 μm, clavate, thin-walled, smooth, clamped. Basidia 75-90 × 8-10 μm, clavate, hyaline, thin-walled to thick-walled, 4-spored, sterigmata 7-10 μm in length. Basidiospores [20/1/1] 8.3-10.1 (-10.3) × 5.3-6.3 (-6.4) μm, Q = (1.34-) 1.47 -1.78 (-1.83), Q m = 1.60 ± 0.09, ellipsoid to broadly ellipsoid, ovate or amygdaliform, with a small apiculus, inamyloid, thin-walled, hyaline in KOH. Leptocystidia 50-65 × 3-5 μm, scattered amongst and scarcely projecting beyond the basidia, cylindrical to narrowly clavate, thin-walled, smooth, hyaline, non-pigmented, clamped, inflated apically at maturity, at times with apical or sub-apical branches. Mycelial hyphae 2-3 μm diam., interwoven or aggregated into rhizomorphic strands, branched, clamped; the hyphal walls echinulate with light microscopy, covered with massive nipple-shaped protuberances, as well as encrusted with prism-like crystals up 5 μm long that are insoluble in KOH.

Chemical reactions.

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

Known distribution and ecology.

NW China, Gansu Province. Solitary on the ground in coniferous woods ( Abies spp.) or mixed with broad-leaved trees ( Betula spp. and Rosaceae ) at elevations of approximately 3000 m.

Materials examined.

China. Gansu Province: Lintan Prefecture, Yeliguan National Forest Park, coniferous woods ( Abies spp.) or mixed with Betula spp. and Rosaceae plants, alt. 3000 m, 10 August 2012, X.T. Zhu 638 (HKAS 76487, Holotype); Wudu Prefecture, September 1992, M.L. Tian M6465 (HMAS 63052).

Comments.

Clavariadelphus gansuensis , currently known only from NW China, is distinct by its slender, clavate, orange basidiomes with truncate apex, ellipsoid basidiospores (8.3-10.1 × 5.3-6.3 μm), pink staining reaction to KOH, hyphae of the basal mycelium with nipple-shaped protuberances and prism-like crystals and solitary growth habit in coniferous or mixed forests.

This species is most likely to be confused with several taxa, including C. amplus , C. pallido-incarnatus , C. pakistanicus , C. truncatus and C. unicolor . The comparison between C. gansuensis and C. amplus can be found in our treatment of C. amplus .

According to our phylogenetic analyses, C. gansuensis is allied with the sequence of " C. truncatus " from GenBank with strong support (Fig. 1 ).

Figures

Figure 1. Phylogenetic tree of Clavariadelphus based on ITS sequence data. RAxML BP values (≥ 50 %) are shown above branches, Bayesian posterior probabilities (≥ 0.90) are shown above branches; new taxa are marked in red.

Figure 2. Clavariadelphus species in China. a C. alpinus (HKAS 57396, holotype) b, c C. amplus (HKAS 54876, holotype) d, e C. elongatus (d from HKAS 50742 e from HKAS 76589) f C. gansuensis (HKAS 76487, holotype) g C. himalayensis (HKAS 58811) h, i C. khinganensis (h from MHHNU 7789, holotype i from MHKMU H. Y. Huang 368) j C. sachalinensis (MHHNU 7816) k, l C. yunnanensis (k from HKAS 49398 l from HKAS 58789).

Figure 3. Basidiospores of Clavariadelphus under light microscope. a C. alpinus (HKAS 57396, holotype) b C. amplus (HKAS 54876, holotype) c C. elongatus (HKAS 76589) d C. gansuensis (HKAS 76487, holotype) e C. himalayensis (HKAS 58811) f C. khinganensis (MHHNU 7789, holotype) g C. ligula (HKAS 35954) h C. sachalinensis (MHHNU 7816) i C. yunnanensis (HKAS 57659).

Figure 4. Basidiospores of Clavariadelphus under SEM. a C. alpinus (HKAS 57396, holotype) b C. amplus (HKAS 54876, holotype) c C. elongatus (HKAS 76589) d C. gansuensis (HKAS 76487, holotype); e, f C. himalayensis (HKAS 58811) g C. khinganensis (MHHNU 7789, holotype) h C. yunnanensis (HKAS 57659).

Figure 5. Hyphae of basal mycelium from Clavariadelphus under SEM. a C. alpinus (HKAS 57396, holotype) b C. amplus (HKAS 54876, holotype) c C. elongatus (HKAS 76589) d C. gansuensis (HKAS 76487, holotype) e C. himalayensis (HKAS 58811) f, g C. sachalinensis (f from HKAS 33844; g from MHHNU 7816) h C. yunnanensis (HKAS 57659).

Figure 9. Microscopic features of Clavariadelphus gansuensis (HKAS 76487, holotype). a Leptocystidia and immature basidia b Basidia.