Fitzroyomyces xishuangbannaensis R.F. Xu & Tibpromma, 2022

Xu, Ruifang, Thiyagaraja, Vinodhini, Dai, Dong-Qin, Karunarathna, Samantha C. & Tibpromma, Saowaluck, 2022, Additions to Fitzroyomyces (Stictidaceae, Ascomycota) from Yunnan Province, China, Phytotaxa 548 (2), pp. 253-266 : 260

Fitzroyomyces xishuangbannaensis R.F. Xu & Tibpromma , sp. nov. ( Fig. 3 )

Index Fungorum Number: IF 559624 ; Facesoffungi Number: FOF 10811

Holotype: HKAS 122682

Etymology: The specific epithet “xishuangbannaensis” refers to Xishuangbanna, in Yunnan Province where the holotype was collected.

Saprobic on dead branch of Hevea brasiliensis . Sexual morph: Apothecial 235–430 high μm, 200–520 diam μm (x̅ = 300 × 400 μm, n = 10), subglobose, unilocular, gregarious, immersed from the substrate, immersed at first and opening by entire pore at maturity. Hypothecium convex. Disc deeply cupulate, whitish to cream. Margins white. Hymenium hyaline, enclosed in a thick gelatinous matrix. Epithecium absent. Excipulum 20–55 μm composed of cells of textura intricata. Paraphyses 1–2 μm wide at the apex, numerous, filiform, septate, unbranched. Asci 160–180× 10–20 μm (x̅ = 173 × 13 μm, n = 11), 8-spored, unitunicate, long cylindrical, short sessile, rounded at the apex. Ascospores 90–180 × 2–4 μm (x̅ = 152 × 3 μm, n = 10), filiform, hyaline, multiseptate, up to 35-septa, finely guttulate when immature, not constricted at the septa and not easily break into different size. Asexual morph: Undetermined.

Material examined: CHINA, Yunnan Province, Xishuangbanna , on a dead branch of Hevea brasiliensis Muell. Arg , 30 July 2021, Ruifang Xu, XSBNR–20, (HKAS 122682, holotype) .

Notes: The nucleotide base pair differences of ITS, LSU and mtSSU sequences are compared between our new species and members of Fitzroyomyces ( Table 2 ). The new taxon was established based on the recommendations outlined by Jeewon & Hyde (2016). We also compared the morphology of our strain with Fit. cyperacearum , Fit. hyaloseptisporus , Fit. pandanicola and Fit. yunnanensis ( Table. 3 ). The differences between Fit. xishuangbannaensis and Fit. cyperacearum are that the larger apothecia (235–430 × 200–520 μm vs. 201–260 × 210–310 μm), wider exciple (17–70 μm vs. 20–55 μm), narrower paraphyses (17–70 μm vs. 24–54 μm), longer asci (110–150 × 10–20 μm vs. 160– 180 × 10–20 μm), longer, and fusiform ascospore guttulate with more septation. Fitzroyomyces xishuangbannaensis differs from Fit. hyaloseptisporus in larger apothecia (235–430 × 200–520 μm vs. 140–200 × 150–200 μm), wider exciple (20–55 μm vs. 6–20 μm), smaller asci (160–180 × 10–20 μm vs. 165–200 × 10–25 μm) and ascospores (90– 180 × 2–4 μm vs. 150–200 × 3.5–6 μm), further, ascospores are fuliform with more septation in Fit. hyaloseptisporus whereas Fit. xishuangbannaensis possesses filiform, hyaline, multiseptate ascospores finely guttulate when immature ( Wei et al. 2021). Fit. xishuangbannaensis and Fit. yunnanensis have the same geographical distribution in China ( Lu et al. 2021) however, the two differ in several morphological characteristics such as Fit. yunnanensis has bigger apothecia, smaller asci, smaller ascospores and septation ( Table 3 ).

A key to species in Fitzroyomyces

1. Septation of ascospores less than 25..................................................................................................................... 2

1. Septation of ascospores more than 25 .................................................................................................................. 3

2a. Guttulate fusiform ascospores, textura intricata to textura angularis exciple......................................................... Fit. yunnanensis

2b. Eguttulate filiform ascospores, textura intricate exciple ...................................................................................... Fit. cyperacearum

3. Guttulate filiform ascospores ............................................................................................................................................................. 4

3. Eguttulate filiform ascospores.................................................................................................................................. Fit. pandanicola

4a. Ascospores commonly presenting 1–3 prominent constrictions (ascospores easily break into different size of fragments................ ........................................................................................................................................................................... Fit. hyaloseptisporus

4b. Ascospores not constricted at the septa and not easily break into different size......................................... Fit. xishuangbannaensis

Figures

FIGURE 3. Fitzroyomyces xishuangbannaensis (HKAS 122682, holotype). A–B Apothecia on a dead stem of Hevea brasiliensis. C Section of an apothecium. D Exciple. E Paraphyses with cotton blue reagent. F, G Asci. H Tip of the asci. I–L Ascospores. M Ascospores stained with cotton blue reagent. Scale bars: C = 200 μm, D = 100 μm, E, H, J, K, M = 30 μm, F, G, I, L = 50 μm