Thelephora atroarenicolor (Nikol.) Kõljalg, I. Saar & Svantesson
2024
Syn.:
Tomentella atroarenicolor Nikol. 1970
Basidiome effused, separable, hypochnoid,
becoming pellicular, soft membranaceous,
rather brittle when dry, up to 0.3 (0.5) mm thick.
Hymenial surface at first
discontinuous, porulose, tufted, then continuous,
smooth to granulose, rarely becoming somewhat colliculose,
uniformly grey brown, brown to dark brown, normally with a slight olivaceous tint (10YR–5Y 5–4/3).
Subhymenium becoming fairly compact, thin or slightly thickening in old parts,
up to 0.1 mm thick.
Subiculum scanty to developed, araneose, hypochnoid, loose, rarely becoming soft fibrous, pale brown
to brown (10YR 6–5/4), paler to almost concolour with
the fertile area.
Margin indistinct and almost fertile throughout to sterile or almost so
and distinct, shortly to indefinitely thinning out, araneose,
much paler than the mature fertile area, very pale brown or pale yellow to
yellow (10YR–5Y 8–6/4).
Rhizomorphs common, obscure or easily seen in subiculum, cracks of the
substratum and infrequently at the margin, compact, flexible, frequently
branched, pubescent, up to 0.1 (0.2) mm thick, brown to dark brown.
Hyphal system monomitic, or doubtfully
dimitic with very thin, thick-walled, richly branched hyphae on surface of
rhizomorphs; generative hyphae mostly with fibulate
primary septa.
Subicular hyphae regular, long-celled, 3.5–5 (7) µm wide, with thin to
thickening wall, normally branching close to the septa, sometimes with simple
anastomosis, subhyaline to yellowish-brown or pale
brown.
Subhymenial hyphae regular and short-celled, 3–4 (5)
µm wide, thin-walled, often branching from clamps, hyaline to subhyaline or very pale yellowish brown.
Rhizomorphs starting as loose strands of few generative hyphae like the subicular ones, becoming compact and slightly structured
with a core of fairly wider and subhyaline hyphae up
to 8 (10) µm surrounded by compactly arranged hyphae (2.5) 3–5 µm in diam.,
with thickening wall and subhyaline to yellowish
brown or pale brown; surface with some richly branched pseudoskeletal
hyphae about 1 (2) µm wide, building an incomplete labyrinthiform
tissue, subhyaline to pale brown or and some
projecting hyphoid cystidia, with thin to slightly
thickening wall, 2–3 µm in diam., not or very slightly expanded apex.
Cystidia present, arising from subicular or
subhymenial hyphae, filiform, hyphoid, not or very
slightly expanded at the apex, up to 110 (160) µm long, 2–3 (4) µm wide along
their length and 3–4 (5) µm wide at apex, projecting, aseptate
or with an intercalar fibulate
septum, with thin or thickening wall, hyaline to very pale yellowish brown.
Basidia when immature often subglobose to pyriform, then clavate to utriform, often transversally septate and soon
collapsed in the upper half after spore discharge, hyaline to very pale
yellowish brown, (20) 30–50 x 8–10 (12) µm; (2) 4 sterigmata,
up to 6 (9) µm long, and 1.5–2 (3) µm wide at the base.
Basidiospores with irregular to sinuous
outline, in lateral view mostly ellipsoid with a flattening adaxial
side, rarely more or less distinctly lobed, in frontal view slightly ovoid
often with sinuous outline, slightly three-lobed; in polar view more or less
globose to irregularly globose, (7.5) 8–10 (10.5) x (6.2) 6.5–7.5 (8) x (7.5)
8–9 (9.5), Q1 = 1.1–1.4, Q2 = 1–1.2 µm, echinulate,
sometimes with dorsal and lateral crowns, ochraceous
to brownish; aculei 0.8–1.8 (2.5) µm long and 0.4–0.8
µm wide at the base, single, sparse, tapering.
Incrustation: almost none or with segments and cystidia coarsely incrusted
by small hyaline crystals.
Chemical reactions: IKI–. CB: – but young spores often distinctly cyanophilous. KOH: elements slightly more brownish (or less
yellowish).
description: Elia Martini
drawings and photo: Elia Martini