Aenigmatomyces ampullisporus R.F. Castañeda & W.B. Kendr., Mycologia 85(6): 1024 (1994) [1993]

Index Fungorum Number: IF 361457; Mycobank Number: MB 361457; Facesoffungi Number: FoF 15879

Hyphae mostly superficial, branched, with exclusion septa, creeping, and adhering closely to the surface of the host/substrate, colorless, hygroscopic, 1-3.5 μm diam. Sporiferous hyphae conspicuous, differentiated, upright or ascending, flexuous, many septate, distal two-thirds fertile and unbranched (rarely branched), smooth-walled and thin-walled, colorless, up to 250 ~μm long, and 3-5 μm wide at the base, 1-3 μm wide near the apex. Sporiferous cells numerous (up to 35 in a linear series incorporated in the axis of a single sporophore), monoblastic, intercalary and terminal, usually short and barrel-shaped or cylindrical, 1.3-4 μm long, 1-2 μm wide; wall smooth, thin and colorless; each cell developing a single, finely tapered, lateral outgrowth which becomes needle-like toward its apex. Juxtaposed cells produce their sporogenous outgrowths more or less on opposite sides of the axis of the sporiferous hypha (or these may possibly arise in a very loose helix along that axis), 1.5-2.5 μm wide and 6-10 μm long towards the apex. Spores solitary, ampulliform, distally rostrate, constricted to a narrow isthmus about one-third of the way down, and with the main, ellipsoidal spore body toward the base, thin-walled, smooth-walled, hyaline, 6-7 × 1-1.3 μm; after secession, spores sometimes bear a broken off fragment of the sporogenous cell at their otherwise rounded base. The entire cytoplasm of the sporifcrous cell migrates into the spore (refer Castañeda et al. 1993).

Holotype – Slide preparation in DAOM 216091. On hyphae and oogonia of Pythium sp. on decaying leaf, Alternate Lookout Trail, Algonquin Park, Ontario, Canada, 1 September 1992, R. F. Castaneda and B. Kendrick (Castaneda no. C92/169).

Other Specimen Examined – On fungal hyphae On dead leaf of Myrica gale L., Spruce Bog Trail, Algonquin Park, 6 September 1991, R.F. Castaneda and B. Kendrick. Slide preparation in WAT.

Figure 1 – Aenigmatomyces ampulisporus. Sporiferous hyphae and spores, showing the close septation of the fertile regions, the needle-like lateral outgrowths of the sporiferous cells, the mode of attachment of the spores, and their morphology.