Macrovalsaria megalospora (Mont.) Sivan. Trans. Br. Mycol. Soc. 65: 400 (1975). Index Fungorum Number: IF317110
≡ Sphaeria megalospora Mont., Annls Sci. Nat., Bot., sér.2 14: 324 (1840)
= Amphisphaeria megalospora (Mont.) Sacc., Syll. Fung.1: 724 (1882)
= Amphisphaeria bambusina Sydow, Philipp. Jour. Sci. 8,274 (1955)
= Amphisphaeria lantanae Ramakrishnan, Proc. Ind.Acad. Sci. 42, 249 (1955)
= Valsaria leonensis Deighton, Sydowia 6, 321 (1952)
= Macrovalsaria leonensis (Deighton) Petrak, Sydowia 15,300 (1961)
Saprobic on dead branches on T. grandis. Sexual morph: Ascomata (305–)535–615(−780) μm high × (510–)840–1010(−1435) μm diam. (x = 535 × 880 μm n = 20), black, scattered, solitary or in linear aggregations, initially immersed, becoming erumpent through bark fissures, sphaeroid to subsphaerical, uniloculate to multiloculate, dark brown to black, base flattened, carbonaceous, with a central ostiole. Ostiole 145–190μm high, 265–290μm wide, circular, central, periphyses, papilla. Peridium 65–150μm thick, composed of three layer; outer layer black, median layer brown, inner white, comprising globose to angular, textura intricata or globulosa at the sides and above, with numerous brown particles, textura angularis to prismatica at the lowest sides. Hamathecium 1.5–2.8μm wide hyphae-like, septate, numer ous, trabeculate pseudoparaphyses. Asci (260–)280− 295(−305) × 34–38μm (x = 280 × 35μm n = 10), 8-spored, bitunicate, fissitunicate, cylindrical to cylindro–clavate, with a short pedicel, apically rounded with ocular chamber. Ascospores (36–)38–40(−42) × 16–20 μm (x = 39 × 18 μm n = 20), mostly uniseriate or biseriate, ellipsoidal to broadly subfusoid, with conical ends, 2-celled, hyaline when young, lacking skull cap-like germ apparatus at the lower end, later pale brown becoming dark brown, with skull cap-like germ apparatus at the lower end, constricted and darkened at median septum, transverse striation near the center of lower cell with 4–6 longitudinal striations from transverse striation to the end cell, surface smooth, granular to verrucose. Asexual morph: Undetermined.
Habitat: Known to inhabit dead branches, dead stems, dead twigs, culms on multiple genera in multiple families (Sivanesan 1975) and on dead branches of T. grandis (current study).
Known distribution: Mainly found in the tropics and subtropics (Sivanesan 1975), e.g. China (Li and Zhuang 2009), India (Sivanesan 1975), Papua New Guinea (Hyde 1994), Taiwan (Wang and Lin 2004) and Thailand (current study).
Material examined: THAILAND, Chiang Rai Province, Muang District, on dead branches of T. grandis, 19 November 2012, M. Doilom & J. Roux, The DNA was extracted from six representative fruiting body on host substrate, MFLU 15–3431, MKT 118/1, GenBank Accession No: ITS:KU712451, SSU: KU712473, TEF1: KU888618, TUB:KU888624, reference sequence designated here; ibid. MFLU 15–3432, MKT 118/2, GenBank Accession No: ITS: KU712452, SSU: KU712476, TEF1: KU888619, TUB KU888625; ibid. MFLU 15–3433, MKT 118/3, GenBank Accession No: ITS: KU712453, SSU: KU712481, TEF1; KU888620, TUB: KU888626; ibid. MFLU 15–3434, MKT 118/4, GenBank Accession No: ITS: KU712454, SSU: KU712482, TEF1; KU888621; ibid. MFLU 15–3435, MKT 118/5, GenBank Accession No: ITS: KU712455, SSU: KU712483, TEF1; KU888622; ibid. MFLU 15–3436, MKT 118/6, GenBank Accession No: ITS: KU712456, SSU: KU712484, TEF1: KU888623.
Notes: Macrovalsaria (Petr.) is presently a monotypic genus (Petrak 1961). The unusual characters are brown ascospores with longitudinal slits (or skull cap-like germ apparatus at the lower end), uniseptate constricted at the septum, the lower cell provided with transverse striations near the center and 4–6 longitudinal striations from the (Table 11). However, the type species of Macrovalsaria (Petrak), Ma. leonensis (Deighton) Petrak is replaced by an earlier epithet as Ma. megalospora in Sivanesan (1975) and is the only one species accepted in the genus (Sivanesan 1975). It is therefore considered to be Ma. megalospora and the strain MFLU 15–3431 is designated as the reference sequence for Ma. megalospora.
FIG. Macrovalsaria megalospora (MFLU 15–3431, reference specimen). a Ascomata on host substrates. b Close-up of ascomata. c Section through ascomata. d Periphyses in ostiole. e Textura angularis to prismatica peridium at the lowest sides. f Textura intricata or globulosa peridium at the side and above. g Trabeculate pseudoparaphyses. h–k Asci with 8-ascospores. l Ascus showing ocular chamber. m–p Ascospores (n–p ascospores with skull cap-like germ apparatus at the basal end). Notes: g, l Stained in lactophenol cotton blue. Scale bars: b= 500 μm, c = 300 μm, d, l = 50 μm, e, m–p = 10 μm, f–k = 20 μm