Boerlagiomyces macrospora V.G. Rao & Varghese [as‘Boerlagomyces’], Sydowia 32(1–6): 254 (1980) [1979]     = Thaxteriella macrospora (V.G. Rao & Varghese) J.L.Crane, Shearer & M.E. Barr, Can. J. Bot. 76(4): 606 (1998)

Saprobic on dead branches of T. grandis. Sexual morph: Ascomata (160–)250–290(−305) μm high × (180–)215– 230(−310) μm diam. (x = 255 × 220μm n = 30), black, solitary to gregarious, scattered, superficial, rough, with hyphae developing from ascomatal base on substrate, vertical section through ascoma; uniloculate, globose to subglobose, reddish brown to dark brown, with setae: up to 30μm long, 4.5–7μm wide. Peridium 25–55 μm thick, composed of textura angularis cells comprising two layers, outer layer comprising black to reddish-brown, thick-walled cells, inner layer comprising hyaline, thin-walled cells. Hamathecium 0.8–1.8μm wide, numerous, hypha-like, filiform, septate, branched, trabeculate pseudoparaphyses, embedded in gelatinous matrix. Asci (105–)130 − 150(−175) × 35–60 μm (x = 135 × 45 μm n = 15), 8-spored, bitunicate, cylindrical to broadly clavate, with a short pedicel, apically rounded, with an ocular chamber. Ascospores (40–)49–52(−58) × 14–19μm (x = 47 × 16μm n = 30), overlapping biseriate to triseriate, fusoid to ellipsoidal, straight or slightly curved, hyaline when young, later pale brown to olivaceous brown, muriform, curved, swollen to enlarged at the center cells, terminal cells subhyaline, with 8–13 longitudinal septa and 9–14 transverse septa, an apiculus at each end. Asexual morph: see culture characteristics.

Culture characteristics: Ascospores germinating on PDA within 24 h. Germ tubes produced at the ends of the ascospores. Colonies on MEA reaching 13–15 mm diam. after 7 days in the dark at 25 °C (x = 14 mm, n = 5), edge entire, flat or effuse on the old mycelium plugs, sparse, slow growing, yellowish brown (5F4) in the center, orange white (5A2) at the edge from above, greyish brown (5F3) at the center and yellowish white (4A2) at the edge from below. Mycelium 3.5– 11μm wide, aerial to immersed, pale brown to reddish brown, septate, branched, slightly constricted at the septa, with some melanin deposits. Chlamydospores developing in culture, catenate, intercalary or terminal, initially hyaline, becoming pale brown to reddish brown at maturity, subglobose to ellipsoidal, 1-celled, thick and smooth walled.

Habitat: Known to inhabit dead wood of a dicotyledonous plant (Rao and Varghese 1979), dead branches of T. grandis.

Known distribution: India (Rao and Varghese 1979), Thailand.

Material examined: THAILAND, Chiang Rai Province, Mae Chan District, on dead branches of T. grandis, 1 July 2012, M. Doilom, (MFLU 15–3422, reference specimen designated here), living culture MFLUCC 12–0388, MKT 061, ICMP 21161, GenBank Accession No: ITS:KU144927, LSU: KU764712, SSU: KU712475, TEF1: KU872750.

Notes: Boerlagiomyces was established by Butzin (1977) with B. velutinus (Penz. & Sacc.) Butzin as the type species. This genus presently comprises eight species according to Index Fungorum (2016). Boerlagiomyces macrosporus has been synonymized with Thaxteriella macrospora by Crane et al. (1998) based on the ascomata being erumpent through bark rather than superficial, loculate and glabrous rather than covered with setae or hyphal appendages. However, Crane et al. (1998) did note that the ascospores were atypical as they are muriformly septate, not a feature of Thaxteriella (which has phragmosporous ascospores). The nomenclature of Crane et al. (1998) is rejected in preference to the name B. macrospora based on phylogenetic analyses (see above). MFLU 15–3422 obtained from T. grandis in this study is identical to AHM 3874 (holotype) as described in Rao and Varghese (1979) in having superficial, globose ascomata, with out setae on the surface, but with black basal mycelium; ascospores sub-ellipsoid, muriform, olivaceous brown, with subhyaline terminal cells and up to 14 transverse septa. The ascoma and ascus dimensions are similar even though ascospore dimensions in the latter are slightly different, as the ascospores might be variable in size due to different substrates. MFLU 15–3422 is treated as B. macrospora and MFLUCC 12–0388 is maintained as a reference specimen for this species.

FIG Boerlagiomyces macrospora (MFLU 15–3422, reference specimen). a, b Ascomata (a = surface view; b = side view) on dead branches. c Wall of an ascoma in surface view with basal mycelium on substrate. d Section though ascoma and basal mycelium on host. e Peridium. f Immature asci and mature asci with immature ascospores. g–i Immature ascospores. j Mature ascospore. Note: f Stained in lactophenol cotton blue. Scale bars: a, b = 200 μm, c = 50 μm, d, g = 20 μm, e, h–j = 10 μm

FIG Morphology of Boerlagiomyces macrospora on media. a Germinated ascospore. b Colony on PDA after 2 months (above and below views). c Colony on MEA after 7 days (above and below views). d Mycelia. e–i Chlamydospores. Note: a Stained in lactophenol cotton blue. Scale bars: a, e = 20 μm, d = 30 μm, f–i = 10 μm