Rhopalostroma brevistipitatum Daranagama & K. D. Hyde, 2015

Daranagama, Dinushani A., Liu, Xingzhong, Chamyuang, Sunita, Bahkali, Marc Stadler Ali H. & Hyde, Kevin D., 2015, Rhopalostroma brevistipitatum sp. nov. from Thailand with an extended generic description for Rhopalostroma, Phytotaxa 227 (3), pp. 229-242 : 238

Rhopalostroma brevistipitatum Daranagama & K. D. Hyde , sp. nov. Figs 3–4 .

Index Fungorum number: IF 550815; Facesof Fungi number: FOF00656

Etymology: —Refers to small, short and stout stipe in stromata.

Diagnosis:— Differs from other species in Rhopalostroma by having small and solitary stromata with short and stout stipe and cylindrical asci with J+, discoid, apical apparatus.

Saprobic on decaying bark. Sexual morph: Stromata (2.3–)2.5–6.4(–6.8) mm high (x = 4.9 mm), erumpent through bark, widely scattered, simple, solitary, never clustered, not fused and not branched, light brown to purplish brown, carbonaceous, stipe (1–)1.3–1.8(–2) × (1.8–)2–3.2(–3.5) mm (x = 1.5 × 2.7 mm), compact, short and stout, head (3.8–)4–4.8(–5) × (1.7–)2–3.7(–3.7) mm (x = 4.5 × 2.9 mm), expanded, clavate, flesh of head greyish black and continuous with that of the stipe, stromatal pigments present, light green. Ascomata (153–)186–393(–398) × (160–)179–226(–234) μm (x = 284× 204 μm), immersed, arranged in a single layer below the convex layer of the head, encased in carbonaceous tissue, individual perithecia hemispherical. Ostioles appear as minute shiny black dots, papillate. Paraphyses at base (2.7–)3–4.2(–4.5) μm wide (x = 3.7 μm), slightly longer than asci, filamentous, aseptate. Asci (80.6–)85.2–102.5(–112.3) μm (x = 98.6 μm) in total length, spore bearing part (60.2–)62.5–83(–85.8) × (4.3)4.5–5(–5.1) μm (x = 77.5 × 4.8 μm), stipe (12.3–)18.5–33.5(–38.2) μm (x = 27.5 μm), 8-spored, cylindrical, stipitate, with an amyloid apical apparatus, discoid, (0.8–)1.2–2(–2.1) × (1.6–)2–2.2 (2.4) μm (x = 1.5 × 2.0 μm). Ascospores (9.6–)10.6–11.3(–11.5) × (3.3–)4–4.5(–4.8) μm (x = 11 × 4.3 μm), uniseriate, olivaceous, equilaterally ellipsoidal, with broadly rounded ends, epispore smooth, perispore indehiscent in 10% KOH, germ slit straight, spore length on the convex side ( Fig. 3a–r ). Asexual morph: Conidiophores (70–)80–97(–110) × (1.5–)2–2.5(–2.8) μm (x = 95.5 × 2.3 μm), simple to complex, hyaline, dichotomously branched, with nodulisporium-like branching pattern. Conidiogenous cells (15–)20–25(–35) × (0.7–)1–1.5(–1.6) μm (x =23.4 × 1.3 μm), developing terminally, cylindrical, hyaline, apically aggregated scars. Conidia (4.2–)5–6.7(–6.9) × (2.3–)2.5–3.2(–3.5) μm (x = 5.5 × 2.8 μm), hyaline, single, ellipsoidal, with one pointed end and one blunt end ( Fig. 4d–k ).

Culture characteristics:— Colonies on OA at 25°C reaching 5 cm in 7 days, at first whitish developing melanized pigments around the center within 5–10 days, azonate with diffuse margins, reverse at first, whitish and turning brownish orange at the center. Distinct sporulating regions observed after 10 days, black ( Fig. 3a–c ).

Material examined:— Thailand, Chiang Rai Province, Mae Fah Luang University Park , on decaying bark, 15 November 2014, D. A. Daranagama, (holotype MFLU 15-2245 !) living cultures, MFLUCC 15-0007 , KIBCC ; ibid (isotype KUN!), ex-isotype, MFLUCC 15-0011 .

Notes:— Rhopalostroma brevistipitatum is a new species of Rhopalostroma based on its unique morphology and phylogenetic analysis. The new species has a faint amyloid apical apparatus; this has not previously been observed in the genus. This species also has comparatively small stromata. R. brevistipitatum differs from other species in the genus by having a short, but stout stipe, as well as asci with J+ apical apparatus which has not been reported in the genus before. The asexual morph was identified as nodulisporium-like which is characteristic of the genus ( Hawksworth & Whalley 1985, Stadler et al. 2010, Daranagama et al. 2014).

Figures

FIGURE 3. Rhopalostroma brevistipitatum (Holotype). a: Developmental stages of stromata. b: Separated mature stromata and KOH extractable pigments. c: Individual stroma showing expanded head and short, stout stipe. d: Stromatal surface with ostoles. e: Longitudinal section of stroma showing perithecia alignment in the periphery of stroma. f: Cross section of the stroma showing perithecia. g-h: Asci in water. k: Paraphyses. l and m: Asci in Melzer’s reagent, Note the presence of an apical apparatus. n-q: Mature ascospores in water. r: Ascospores with germ slit. Scale bars: c = 1000 μm; d = 500 μm; e = 200 μm; f = 1000 μm; g-j = 10 μm; k-m = 5 μm; n-r = 10 μm.

FIGURE 4. Rhopalostroma brevistipitatum in OA after 2 weeks (MFLUCC 15-0007-ex-type). a: From above. b: From below. c: Development of coniomata in the culture. d-g: Conidiophores from simple to more complex structure. h-k: Conidia. Scale bars: d-g = 40 μm; h = 10 μm; i-k = 5 μm.