Annulohypoxylon palmicola J.K Liu & K.D Hyde, sp.

Index Fungorum number: IF551428; Facesoffungi number: FoF00984; Figs. 2 and 3
Etymology – Named after the palm host on which the fungus was collected.
Holotype –  MFLU 15-0040

Saprobic on palms. Sexual morph Stromata effuse pulvinate, 3.5 – 93 mm long, 2.5 – 22 mm broad, 0.95 – 1.5 mm high (excluding ostiolar necks), with inconspicuous to 1/3 exposed perithecial mounds, developing within bark, erumpent through the periderm, yielding a dull green pigment in 7 %KOH; surface dull black, strongly uneven owing to stout; stromatal crust strongly carbonaceous; interperithecial tissue blackish, powdery, without visible granules. Ascomata 0.6 – 0.95 mm high, 0.3 – 0.7 mm diam., obovoid to flask – shaped, completely encased in thick carbonaceous tissue. Ostioles conical, papillate, encircled with a flattened truncatum – type disc, 0.1 – 0.2 mm diam. Paraphyses not seen. Asci 74 – 170 × 4.5 − 7 μm (x̄ = 125 × 5.5 μm, n = 25), 8 – spored, unitunicate, cylindrical,fragile and readily deliquescing, with long pedicel, up to 50 μm, without a visible apparent apical apparatus, not bluing in Melzer’s reagent. Ascospores 12–14.5×3.5−5 μm(x =13.5× 4 μm, n=60), fusiform, 1-septate, brown to dark brown, with a faint, curved, germ slit ca. 3/5th of the spore length, lacking cellular appendages or a gelatinous sheath; epispore smooth.

Material examined – THAILAND, Chiang Rai Province, Muang District, Khun Korn Waterfall, on dead sheath of Arenga westerhoutii Griff. (Arecaceae), 11 September 2010; Jian-Kui Liu, JKA 0037 (MFLU 15-0040, holotype), ex-type living culture, MFLUCC 11-0020.

Notes – This is a typical species of Annulohypoxylon in having pale brown fusoid ascospores and is most similar to A. leptascum, but differs by its slightly smaller ostiolar discs 0.1 – 0.2 vs 0.2 – 0.3 mm (Hsieh et al. 2005; Fournier et al. 2010). The phylogenetic analysis showed that the Annulohypoxylon species clustered together and formed a well-supported clade; within this clade, the new species A. palmicola clustered together with A. urceolatum (Rehm) Y.M. Ju, et al., and A. leptascum var. macrosporum and shows a close relationship with them?. These species share similar morphological characters, but form distinct species in the phylogenies (Fig. 1).

Fig. 1 Phylogram generated from RAxML based on combined ITS and LSU sequenced data for taxa of Xylariaceae. Maximum likelihood bootstrap support values greater than 50% are indicated above the nodes. Only ex-type and voucher strains are used and the new isolates are in blue. The tree is rooted with Sordaria fimicola.

Fig. 2 Annulohypoxylon palmicola (holotype) a, b Stromatal habit c Necks d, e Section through stroma f The structure of the white deposit on the discs of the ascoma. Scale bars: a = 3 mm, b, c = 1 mm, e = 0.5 mm, f = 10 μm.

Fig. 3 Annulohypoxylon palmicola (holotype) a – c Ascus d Ascospores. Scale bars: a, b, c = 50 μm, d = 10 μm.