Chaenothecopsis tigillaris
Thallus: absent, non-lichenised; saprophytic on the hymenophore surface of basidiomata.
Anamorph: not known.
Teleomorph: Ascomata black, stalked apothecia, somewhat glossy, non-pruinose, stalk mainly 150-200 μm tall. Stalk 35-50 μm wide below the capitulum, consisting of dense intertwined brownish and torulose hyphae, 2-2.5 μm wide, periclinally orientated forming a textura intricata, becoming paler towards the base. Capitulum hemispherical, expanding abruptly from the stalk, surface convex, ± smooth, not forming a mazaedium, 195-210 μm diam. Exciple lecideine, dark brown, 4-7.5 μm thick, 2 or 3 cells deep, composed of short-torulose hyphae with somewhat angular isodiametrical cells, ca 3.5-4.5 μm diam., non-continuous below the hypothecium. Hypothecium dark brown, poorly developed, formed by a continuation of the stalk hyphae expanding radially and periclinally, textura intricata, ca 50 μm high. Hymenium hyaline, 65-75 (-80) μm tall. Epithecium continuous, persistent, brown, 4.5-6.5 μm thick, formed of adhering almost pseudoparenchymatous cells, individually 3-4.5 μm diam., with somewhat unevenly thickened walls, formed from terminal branches of interascal filaments. Asci persistent, narrowly cylindrical, unitunicate, 45-52 x 2.5-3.5 (-3.5) μm, 8-spored. Ascospores uniseriately arranged in the ascus, ellipsoidal, with slightly pointed ends, olive-brown, 1-septate, with darker brown septum and spiral ornamentation in the outer cell wall, 4.5-7 x 2-3 μm.
Chemistry: No chemical changes have been detected in any part of the ascomata after the application of 10% KOH.
Image of lectotype: here.
Not formally assessed, but likely to be extinct in Britain. It is only known from three historical vouchers and a single locality in Northamptonshire, thought its polypore host – though non-native – is known from other midland and southern counties of England on construction timbers.
The species was first described from England, and no further records are known from Europe. However, the species might have been overlooked in central and southern Europe where the host polypore Perenniporia meridionalis is more widespread on rotting wood of forest trees and roof timbers. Recently found British material of P. meridionalis was growing on imported wood from France, but Chaenothecopsis tigillaris was absent.
The species is probably saprophytic on a wood inhabiting polypore: Perenniporia meridionalis. This polypore occurs preferably on dead and rotting wood of oaks (Quercus robur and Q. ilex) in forest areas, but also on conifers. In Britain, as well as in other more northern European locations, the host has been mostly reported from worked timber.