Tremella australe F. Wu, L.F. Fan & Y.C. Dai, 2021

Fan, Long-Fei, Alvarenga, Renato Lucio Mendes, Gibertoni, Tatiana Baptista, Wu, Fang & Dai, Yu-Cheng, 2021, Four new species in the Tremella fibulifera complex (Tremellales, Basidiomycota), MycoKeys 82, pp. 33-56 : 33

Tremella australe F. Wu, L.F. Fan & Y.C. Dai sp. nov.

Figs 3B , 5

Holotype.

China Yunnan, Ruili, on fallen angiosperm branch, 23 April 2018, F. Wu 154 (BJFC028064).

Etymology.

Refers to the distribution of this species in South Asia.

Basidioma.

Sessile, when fresh soft gelatinous, creamy-white to beige, translucent, cerebriform, with thick and undulate lobes, up to 4.0 cm long, 2.0 cm broad and 2.0 cm high from base, distinctly shrinking into a film and becoming pale yellow when dry, broadly attached to substratum.

Internal features.

Hyphae hyaline, smooth, thin- to slightly thick-walled, 1.5-6.0 µm in diameter, branched, interwoven, with abundant clamp connections, clamp complexes and anastomoses, slightly thick-walled hyphae usually present near to base of basidioma and sometimes swollen up to 8.5 μm; hyphidia hyaline, smooth, thin-walled, usually derived from the same hyphae with basidia; swollen cells, vesicles and haustoria absent; mature basidia thin-walled, globose to subglobose, with a basal clamp connection, 14.0-19.0 × 13.0-17.0(-18.0) μm, L = 16.3 µm, W = 15.8 µm, Q = 1.03 (n = 30/1), sometimes their width greater than length, usually longitudinally septate, 2-4-celled, with obvious oil drops; sterigmata up to 20 μm long, 1.0-2.5 in diameter, slightly protuberant at apex; probasidia thin-walled, globose to subglobose, mostly proliferating directly from basidial clamps; basidiospores hyaline, thin-walled, broadly ellipsoid to ellipsoid, apiculate, with oil drops, 8.0-10.0 × 6.0-8.0 μm, L = 8.6 µm, W = 7.3 µm, Q = 1.18-1.28 (n = 60/2), germinating by germ tubes or secondary spores; conidia absent.

Additional specimen examined.

(paratype) China Taiwan, Yilan, Linmei Road, on fallen angiosperm branch, 20 June 2009, Y.C. Dai 11539 (BJFC007408).

Notes.

Tremella australe formed an independent lineage with high support in our phylogenies (Figs 1 , 2 ). The species is easily confused with T. guangxiensis by sharing whitish, translucent cerebriform basidioma and similar basidia and basidiospores, but T. guangxiensis has branched hyphidia and umbelliform conidiophores. Besides, T. australe are different from T. subfibulifera , T. guangxiensis and T. " Tremella neofibulifera " by 7.82%, 5.94% and 6.82% sequence differences in the ITS sequences and 2.13%, 3.43% and 1.25% in the partial nLSU sequences respectively.

Figures

Figure 1. The Maximum likelihood tree showing phylogenetic relationship of species in Tremella s. s. based on the ITS + partial nLSU dataset. Bootstrap support values for MP and ML greater than 50 % and BI greater than 0.95 are given at each node respectively. The samples used in this study are in bold.

Figure 2. The Maximum likelihood tree showing phylogenetic relationship of species in Tremella s. s. based on the combined ITS + partial nLSU + mtSSU + TEF 1 + RPB 1 + RPB 2 dataset. Bootstrap support values for MP and ML greater than 50 % and BI greater than 0.95 are given at each node respectively. The samples used in this study are in bold.

Figure 3. Basidioma A Tremella fibulifera (Alvarenga 471) B T. australe (Wu 154) C T. guangxiensis (Wu 3) D T. latispora (Dai 17568) E T. " Tremella neofibulifera " (Wu 244) F T. subfibulifera (Alvarenga 334). Scale bars: 1 cm (A-F).

Figure 5. Microscopic structures of Tremella australe (Wu 154) A basidiospores B germination tubes of basidiospores and secondary spores C-F basidia at different stages G hyphae with clamp connections and clamp complexes H hyphidia I a section of hymenium. Scale bars: 10 μm (A-I).