Vexillomyces atrovirens

On wet decaying ground wood in an advanced state of decay, with sessile, circular, grain-like fruit bodies, 0.4 to 0.7 mm in diameter, very dark green to black, of soft and gelatinous consistency.

Excipulum of textura intricata, with slightly thick-walled hyphae, 5 to 12 µm wide, with abundant olive-brown pigment inside.

Asci cylindrical to slightly clavate, eight-spored (octosporic), bitunicate, 75 to 100 µm long by 11 to 16 µm wide, with basal croziers, and inamyloid in Melzer's reagent or Lugol's solution.

Paraphyses filiform, septate, 1.5 to 2 µm wide, with apical branching, with swellings of the apical cells 3 to 5 µm wide, slightly projecting above the level of the asci.

Ascospores fusiform, with numerous transverse and longitudinal septa (muriform), measuring within the ascus 15 to 21 µm long by 4.5 to 5 µm wide; inside the ascus these ascospores rapidly produce microspores or microconidia, which are hyaline, 2 to 3 µm long by 1 µm wide, and end up occupying virtually the entire interior of the ascus.

Herbarium material available: JTP2084/24 and 2507/25.