Pleosporales » Macrovalsariaceae » Macrovalsaria

Macrovalsaria megalospora

Macrovalsaria megalospora (Mont.) Sivan. Trans. Br.

≡ 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)

Facesoffungi number: FoF01868.

 

Saprobic on dead branches on T. grandis. Sexual morph: Ascomata (305–)535–615(−780) μm high × (510–)840–1010(−1435) μm diam. (x̄ = 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 145–190 μm high, 265–290 μm wide, circular, central, periphyses, papilla. Peridium 65–150 μm 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 par- ticles, textura angularis to prismatica at the lowest sides. Hamathecium 1.5–2.8 μm wide hyphae-like, septate, numerous, trabeculate pseudoparaphyses. Asci (260–)280 −295(−305) × 34–38 μm (x̄ = 280 × 35 μm 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.

 

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 transverse striation to end of the cell (Sivanesan 1975; Hyde 1994). The morphology of material in this study was compared with Ma. megalospora from other previous descriptions (Hyde 1994; Petrak and Deighton 1952; Sivanesan 1975; Wang and Lin 2004). Ascospore size of this material is most similar to Ma. leonensis (= Valsaria leonensis) Deighton (Petrak and Deighton 1952), and ascospore shape as well as ascomata and asci sizes are also similar to Ma. leonensis as reported in Petrak and Deighton (1952). 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.

 

 

 

Figure X. 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.

 

 

References: Doilom M, Dissanayake AJ, Wanasinghe DN, Boonmee S, et al. (2016) Microfungi on Tectona grandis (teak) in Northern Thailand. Fungal Diversity 39: 1–76.

 

Hyde KD (1994) Fungi from rachides of Livistona in the Western Province of Papua New Guinea. Bot J Linn Soc 116:315–324.

 

Petrak F (1961) Macrovalsaria Petr. n.gen., eine neue dothideale Pyrenomyzetengattung. Sydowia 15:297–300.

 

Petrak F, Deighton FC (1952) Beiträge zur Pilzflora von Sierra Leone. Sydowia 6:309–322.

 

Sivanesan A (1975) Redisposition and descriptions of some Amphisphaeria species and a note on Macrovalsaria. Trans Br Mycol Soc 65:395–402.

 

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