Marchandiobasidium aurantiacum
Marchandiobasidium aurantiacum Diederich & Schultheis 2003, in Diederich et al., Mycological Research, 107, 523-527 (2003).
Diagnosis: Basidiomata light orange (same colour as sclerotia of Marchandiomyces aurantiacus), effused, thin, adnate, granulose, floccose, margin indeterminate, reaching 1 cm diam. Hymenium comprising one or several layers of basidia on vertically branching, thin-walled hyphae. Basidia initially elongate cylindrical, sometimes with a basal, lateral, ellipsoid probasidial bladder, to 57×11 µm; when mature, generally becoming clavate to suburniform, exceptionally with one thin, transverse septum in the upper third, 25–40×12–15 µm, distinctly wider than the supporting hyphae; wall 0.6–0.8 mm thick; basal clamps lacking; basal septum with dolipore visible by light microscopy. Sterigmata 4 per basidium, to 6.5 mm long and 3 mm wide at the base, curved. Basidiospores hyaline, smooth, usually aseptate, nonamyloid, not repetitive, pyriform or lacriform, one side frequently flattened or slightly concave, with a prominent truncate apiculus of 1.5–3 µm diam, 13–17.5 (–18.5) × 8–11.5(–13.5) µm; wall 0.5–1 µm thick; exceptionally with one thin, transverse septum, and then wall distinctly constricted at this septum; dolipore of septum visible by light microscopy. Hyphidia, cystidia and other sterile hymenial elements lacking. Basal hyphae hyaline, occasionally contorted, 3.5–6 µm thick, cells 7–25 µm long, wall 0.5–1 µm thick; dolipores (observed in phase contrast) 0.5–1 µm wide, 0.5–1 µm thick. Superior hyphae hyaline, thin-walled, lacking clamps, septate, 2–4 µm thick. Conidial morph unknown.
Index Fungorum Number: IF372918
Figs 1–3. Marchandiobasidium aurantiacum (holotype). Figure 1. Dead thallus of Physcia tenella with sclerotia (young basidiomata were present on the same thallus). Figure 2. Dead thallus of P. tenella with developing basidioma. Figure 3. Mature basidioma. Bar=250 µm.
Figure 4. Marchandiobasidium aurantiacum (holotype). (a) Basal hyphae; (b) young basidia; (c) immature basidia with the two on the left showing a basal lateral probasidial bladder; (d) mature basidia (in some, only two or three of the four sterigmata are seen); and (e) basidiospores. Bar=10 µm.
Reference:
Diederich, P., & Schultheis, B., & Blackwell, M. (2003). Marchandiobasidium aurantiacum gen. sp. nov., the teleomorph of Marchandiomyces aurantiacus (Basidiomycota, Ceratobasidiales). Mycological Research, 107, 523-527.
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