Botryobasidium coniferarum S.L. Liu & L.W. Zhou, sp. nov.
Index Fungorum number: IF 901058; Mycobank number: MB 901058; Facesoffungi number: FoF 14811; Figs. 1, 2
Etymology – coniferarum (Lat.) referring to occurrence on conifers.
Holotype – LWZ 20210928–3 (HMAS).
Diagnosis – Differing from Botryobasidium conspersum in thick-walled hyphae in subiculum (Bernicchia and Gorjón 2010).
Basidiomes resupinate, thin, separable, up to 15 cm long, 6 cm wide, 150 µm thick. Hymenophore smooth, arachnoid, whitish to cream when fresh, honey-yellow to olivaceous buff when dry, not cracked. Margin white, thinning out as byssoid, finely fibrillose, 0.5 mm wide.
Hyphal system monomitic; generative hyphae without clamp connections; subhymenial hyphae hyaline, thin-walled, 6–8 µm in diam; basal hyphae hyaline to yellowish, thick-walled, frequently branched at right angles, 6–10 µm in diam. Cystidia absent. Basidia subcylindrical, 16–20×7–9 µm, 6-sterigmata, simple-septate at the base. Basidiospores navicular, hyaline, thin-walled, smooth, IKI–, CB–, 7–8×3–3.5 µm, L=7.5 µm, W=3.3 µm, Q=2.3 (n=60/2). Anamorph not found.
Material examined – China, Guizhou Province, Jiulong County, Wuxuhai Scenic Spot, on fallen branch of Pinus, 28 September 2019, L.W. Zhou, LWZ 20210928–3 (HMAS, holotype); ibid., on fallen branch of Pinus, 28 September 2019, L.W. Zhou, LWZ 20210928–4 (HMAS); Sichuan Province, Xichang, Luojishan Scenic Spot, on fallen branch of gymnosperm, 11 August 2019, L.W. Zhou, LWZ 20190811- 36a (HMAS). VIETNAM, Da Lat, Bidoup Nui Ba National Park, on fallen branch of Pinus, 16 October 2017, L.W. Zhou, LWZ 20171016–5 (HMAS), LWZ 20171016–15 (HMAS).
GenBank numbers – LWZ20171016-5: ITS = OR557261; LSU = OR527285; LWZ20171016-15: ITS = OR557262; LSU = OR527286; LWZ20190811-36a: LSU = OR527284; LWZ 20210928-3: ITS = OR557259; LSU = OR527282; LWZ LWZ 20210928-3: ITS = OR557260; LSU = OR527283.
Notes – Besides differing from the most phylogenetic close (Fig. 3) and morphological similar species Botryobasidium conspersum in thick-walled subicular hyphae (Bernicchia and Gorjón 2010), B. coniferarum also resemble Botryobasidium chilense and B. yutajense. However, B. chilense, originally described from Chile and New Zealand, is separated by broadly rounded basidiospores with a lateral and prominent basal apiculus at the base (Holubová-Jechová 1980) and B. yutajense differs in its shorter basidiospores (6–7 µm in length, Ryvarden et al. 2005).
Figure 1 – Basidiomes of Botryobasidium coniferarum (LWZ 20210928–3, holotype). Scale bars: a=1 cm, b=1 mm
Figure 2 – Microscopic structures of Botryobasidium coniferarum (LWZ 20210928–3, holotype). a A vertical section of basidiomes. b Hyphae from subiculum. c Basidiospores. Scale bars: 10 μm
Figure 3 – Phylogeny generated by the maximum likelihood algorithm based on combined ITS and nLSU regions is presented along with the bootstrap values and the Bayesian posterior probabilities above 50% and 0.8, respectively, at the nodes. Holotype is in bold and the newly generated sequences are in blue. Dacrymyces stillatus UPS:F-939814 was selected as the outgroup taxon