back

Thelephora ochraceo-olivacea (Litsch.) Kõljalg, I. Saar & Svantesson 2024

Syn.: Tomentella ochraceo-olivacea Litsch. 1933

Basidiome effused, adherent, tufted, somewhat tomentose to membranaceous, up to 0.1 (0.2) mm thick.
Hymenophore at first pruinose, porulose, finely discontinuous and sometimes slightly granulose or shallowly colliculose, then more continuous and smoother but never polished, slightly subceraceous, pale yellowish, pale ochraceous to mustard yellow when dry, about 2.5Y 8–6/4–6.
Subhymenium thickening, concolour with the fertile area.
Subiculum scanty or poorly developed, up to 30 (50) µm thick, tomentose, slightly paler to concolour with the fertile area.
Margin abrupt or thinning out, pruinose, araneose, sometimes fibrillose, rarely fimbriate, concolour to whitish.
Rhizomorphs infrequent in subiculum and at the margin (in some specimens may be very difficult to find), more common in cracks of the substratum or on the reverse side of the bark (if any), up to 0.2 mm thick, loose to compact, yellowish.

Hyphal system monomitic; most hyphae with fibulate primary septa.
Subicular hyphae regular, fibulate or rarely with some simple septa, (2) 3–5 µm, with thin or slightly thickening wall, smooth, hyaline to very pale yellow.
Subhymenial hyphae almost regular, fibulate, (2.5) 3–5 µm, rarely with intercalary swellings up to 8 µm (remains of collapsed basidia), thin-walled, hyaline to subhyaline.
Rhizomorphs simple or poorly differentiated, built up by regular generative hyphae, with frequent fibulate septa and spaced to close up secondary septa, (2) 3–5 µm wide, branching at some distance from septa, anastomosis rather frequent, short and simple, with thin to thickening walls, sometimes also with localized thickenings, subhyaline; well developed rhizomorphs with slightly wider hyphae in the core reaching 8 (10) µm in diam., with spaced clamps and sometimes with some simple septa, with relatively thin walls, subhyaline to pale yellowish.
Cystidia absent; in some collections rare broadly clavate or pyriform cells may be enclosed in subhymenium or hymenium, about 20 x 14 µm.
Basidia utriform, often with a short narrowed stem, sometimes more or less clavate, sinuous, (35) 40–70 (80) x (8) 9–11 (12) µm (top), 6–11 µm (lower half), with a fibulate basal septum; 4 sterigmata up to 6 (8) µm long.
Basidiospores mostly with irregular outline to lobed, in lateral view more or less irregularly ellipsoid with a flattening adaxial side; in frontal view subovoid to three-lobed; in polar view, globose to three-lobed, (6) 6.5–8 (8.5) x (4.5) 5–6 (6.5) x (5.5) 6–7 (7.5) µm, Q¹ = 1.2–1.4 (1.5), Q² = 1.1–1.3 (1.4), echinulate, yellowish, slightly darker than other elements; aculei up to 1.5 (2) µm long.
Chlamydospores absent.
Incrustation: none.
Chemical reactions: IKI–; CB: hyaline to subhyaline hyphae and young basidiospores more or less distinctly cyanophilous; KOH: hymenophore slightly darkening, context and subiculum often distinctly darkening but no appreciable reaction visible in squash mounts.

description: Elia Martini

drawings and photo: Elia Martini