Annulohypoxylon michelianum
Annulohypoxylon michelianum (Ces. & De Not.) Y.M. Ju, J.D. Rogers & H.M. Hsieh, Mycologia 97(4): 859 (2005)
Basionym: Hypoxylon michelianum Ces. & De Not. 1863
Index Fungorum number: IF 500312; Facesofungi number: FoF 02995
Saprobic on dead wood of Laurus sp. Sexual morph: Stromata effused-pulvinate, with ascomatal mounds 1/3 to 1/4 exposed, 1.2–2 mm thick; surface more or less whitish, pruinose, becoming blackish; blackish granules immediately beneath surface, with KOH-extractable citrine green (67), amber (47), or honey (64) pigments; tissue below the ascomatal layer dark brown, up to 1.2 mm thick. Ascomata sphaerical, 0.5–0.6 mm diam., ostioles conical-papillate, encircled with a slightly concave truncatum-type disc 0.2 mm diam. Asci 8-spored, cylindrical, 190–255 μm total length, the spore-bearing parts 110–120 μm long × 5–6 μm broad, the stipes 80–140 μm long; with J+, apical ring, bluing in Melzer’s reagent, discoid, 0.5–0.9 μm high × 2–2.7 μm broad. Ascospores brown to dark brown, unicellular, ellipsoid-inequilateral, with narrowly to broadly rounded ends, 11.7–14.1 × 4.3–5.2 μm, with straight germ slit, spore-length, perispore indehiscent in 10% KOH, smooth, epispore smooth. Asexual morph: unknown
Material examined: ITALY: Pisa, Hort. Bot., 1861, O. Beccari, wood of Laurus (BPI, holotype of H. michelianum).
GenBank:
Notes: Annulohypoxylon michelianum is only known by specimens collected in Europe inhabiting Laurus sp. The type collection has only a small piece of the stroma but it preserves the typical macroscopic and microscopic characteristics of the species.
Figure x. Annulohypoxylon michelianum (BPI, type of H. michelianum). a Herbarium details b Small piece of the stroma showing the ascomatal mounds and ostiolar discs. c Detail of the ostiolar disc (arrows). d Section of stroma showing ascomata. e Ascal tips in Melzer’s reagent showing amyloid apical ring (arrows). f KOH-extractable pigments. g Asci in Melzer’s reagent. h Ascospores in 10 % KOH solution. i Ascospores in 3% KOH solution showing germ slit (arrow). Scale bars b = 1 mm, c, d = 0.5 mm, e, g, h, i = 10 μm.
References:
Daranagama DA, Hyde KD, Sir EB, Thambugala KM et al. 2018 – Towards a natural classification and backbone tree for Graphostromataceae, Hypoxylaceae, Lopadostomataceae and Xylariaceae. Fungal Diversity 88, 1–65.
Last update: 23 July 2021