Pseudodactylaria brevis C.G. Lin, McKenzie & K.D. Hyde, in Lin, McKenzie, Bhat, Liu, Hyde & Lumyong, Phytotaxa 369(4): 245 (2018)

Index Fungorum number: IF 554780; MycoBank number: MB 554780; Facesoffungi number: FoF 04684.

Etymology – In reference to the short conidiophores.

Holotype – MFLU 18-1037

Saprobic on the plant host. Asexual morph: Colonies on plant substrate effuse, grey-white. Mycelium partly superficial. Conidiophores macronematous, mononematous, solitary, erect, sometimes branched, straight or flexuous, septate, hyaline, cylindrical with apex sometimes inflated, smooth, often reduced to conidiogenous cells. Conidiogenous cells polyblastic, integrated, sympodial, terminal, sometimes becoming intercalary, denticulate, cylindrical, hyaline, 11–25 × 2–5 μm; denticles numerous, cylindrical, flat-topped, up to 1 μm wide. Conidia solitary, dry, acropleurogenous, simple, smooth, prominently guttulate, with 1 median transverse septum, fusiform, sometimes clavate, subtruncate at the base, subobtuse at apex, hyaline, 11.5–17.5 × 2.5–4.0 μm (x̄  = 14.7 × 3.2 μm, n = 40).

Culture characteristics – Conidia germinating on PDA within 12 h. Colonies on PDA effuse, greyish white from above, greyish yellow from below, reaching a diam. of 2–3 cm in 14 days at 25 °C.

Material examined – THAILAND. Krabi: Wat Thum Sua, on decaying wood, 15 December 2015, S. Tibpromma, M 1-1 (MFLU 18-1037, holotype; HKAS 102201, isotype), ex-type living culture MFLUCC 16-0032, KUMCC. ibid., M 1-5 (MFLU 18-1038; HKAS 102202), living culture MFLUCC 16-0034, KUMCC.

Notes – Morphologically, Pseudodactylaria brevis can easily be distinguished from the two other accepted Pseudodactylaria species. Pseudodactylaria brevis often has its conidiophores reduced to conidiogenous cells a feature not occurring in the other species. Most noticeably, the conidia of P. brevis are smaller (11.5–17.5 × 2.5–4.0 μm) than those of P. hyalotunicata (20–25 × 2.5–3) and P. xanthorrhoeae (20–33 × 3–4 μm). Dactylaria chrysosperma (Sacc.) Bhatt & Kendrick is morphologically the most similar species in Dactylaria sensu lato to Pseudodactylaria brevis (Ellis 1976, de Hoog 1985, de Hoog & van Oorschot 1985, van Oorschot 1985, Goh & Hyde 1997, Paulus et al. 2003, Seifert et al. 2011, Crous et al. 2017). Both D. chrysosperma and P. brevis have fusiform, 1-septate, hyaline conidia. However, the conidiophores of P. brevis are hyaline whereas those of D. chrysosperma are brown, paler towards the apex, longer and wider. In addition, Dactylaria chrysosperma produces larger (18–26 × 3–4 μm) and hyaline or yellowish conidia.

Figure 1. Pseudodactylaria brevis (MFLU 18-1037, holotype). a Host material. b Conidiophores on the host surface. c–e Conidiophores, conidiogenous cells with denticles and conidia. f–i Conidia. Scale bars: b = 100 μm, c, d = 10 μm, e–i = 5 μm