Corynesporopsis acaciae R. Kirschner, 2015

Kirschner, Roland, 2015, Phylogenetic placement of a new species of Corynesporopsis from dead acacia wood indicates occurrence of tretic conidiogenesis within Xylariales, Phytotaxa 192 (1), pp. 24-34 : 27

Corynesporopsis acaciae R. Kirschner , sp. nov. ( FIGS 2‒3 ),

Index Fungorum IF550699

Type:— TAIWAN. Taoyuan County: Jhongli City, National Central University, campus, ca. N 24°58'8", E 121°11'45", ca. 100 m, on dead wood of Acacia confusa , 25 October 2013, R. Kirschner 3967 ( TNM F 0027936, holotype!, ex-type culture BCRC FU 30235). ibid., 9 April 2014, R. Kirschner 4015 ( K ( M) 193568, paratype).

Differs from other Corynesporopsis species with 1-septate conidia by conidiogenous cells being darker than the subtending cells and by shorter conidiophores and conidia.

Colonies dark brown, effuse. Hyphae closely attached to the substrate, pale brown, smooth, 2–3 μm. Conidiophores closely aggregated to each other, mononematous, distinct from vegetative hyphae, simple or with a lateral branch at the base, erect, straight, cylindrical, often somewhat constricted at the septa, 0–3-septate, smooth and thick-walled, (10–)11–17(–25) × 4–5 μm (n = 30), but in overmature specimens up to 50 μm long, medium to dark brown, basal cell mostly pale brown. Conidiogenous cells monotretic, terminal, determinate or rarely forming an additional, smaller conidiogenous cell, straight and cylindrical to slightly clavate, rarely obclavate or slightly curved, cell wall conspicuously thicker (0.5–1 μm) than that of the other conidiophore cells, medium to dark brown, mostly darker than the basal cell(s), rarely of the same color or paler, (6–)7–9(–11) × 4–5 (n = 30). Conidia ellipsoidal to cylindrical, straight, broadly rounded at the ends, 1-septate, septum thickened and darkened, smooth, slightly thick-walled (0.5–1 μm), dark brown, (10–)11–13 × (4.5–)5(–5.5) μm (n = 30, in phase contrast; in transmitted light appearing 0.5–1 μm smaller), basal cell often 0.5–1 μm shorter than the distal one, up to ten conidia forming dark brown acropetal, unbranched chains which remain quite stable in light microscopical preparation.

In culture, the fungus differs morphologically from in vivo by predominantly hyaline, only occasionally pale brown hyphae, and occurrence of branched conidiophores.

Additional material examined: — TAIWAN. Taoyuan County, Yangmei City, Tea Research & Extension Station, on dead wood of Acacia confusa ( Fabaceae ), 22 March 2014, R. Kirschner 4012 ( TNM F 0027937).

Etymology: —Referring to the substrate, acacia wood.

Known distribution: —Hitherto only known from Taiwan.

Figures

FIGURE 2. Corynesporopsis acaciae. a. Habitat formed by stump of Acacia confusa at type locality. b. Ex-type culture on corn meal agar with red pigment diffusing from the dark brown colony.

FIGURE 3. Corynesporopsis acaciae, microscopic characteristics. a. Conidiophores and conidia from the holotype. b. Conidiophores from another, overmature specimen. c. Conidiophores from the ex-type culture shown in 2b. Scale bars: c, d, e = 10 μm.