A probably very rare Pinhead found on lignum, which has been over recorded due to an assumption that the lack of white-pruinose apothecia typical of Calicium glaucellum definitively identifies C. abietinum. It does not, C. glaucellum can often lacks the band of white pruina on the apothecia head. Calicium abietinum never has this white pruina, but this, combined with a shiny black or dark brown stalk, as a field character suggests this speces, but the identity needs confirming by spore size and shape.
Thallus immersed. Apothecia 0.6–0.9 mm tall, 6–11 times as high as the width of the stalk, shiny black or dark brown, pruina absent, I–; head 210–280 µm diam., lens- or slightly bell-shaped; stalk 80–130 µm diam. Asci 44–52 × 4–5 µm, cylindrical. Ascospores 11.5–15 × 5–7 µm, uniseriately arranged, minutely warted to minutely cracked-areolate. C–, K–, KC–, Pd–; lichen products not detected by TLC.
Characterised by the non-pruinose apothecia, the black to frequently brownish or olivaceous stalks and the large, minutely warted ascospores. Formerly often incorrectly recorded for Calicium glaucellum, which has smaller, often faintly white-pruinose apothecia, black stalks athat are not shiny, shorter asci and smaller ascospores with minute, irregular ridges and cracks.
On wood, especially Oak and conifers, also decaying stumps and logs.
Probably very rare, but most records, refer to C. glaucellum, so distribution unclear
Altghough most records are probably errors, good matterial has been found recently, but there are few confirmed records, which suggets it is very rare. Likley to be a Red List species, but currently can only be assesed as Data Deficient
Britain: Data Deficient
Cannon, P., Prieto, M., Coppins, B., Sanderson, N., Scheidegger, C. & Simkin, J. (2021). Caliciales: Caliciaceae, including the genera Acolium, Amandinea, Buellia Calicium Diploicia, Diplotomma, Endohyalina, Monerolechia, Orcularia, Pseudothelomma, Rinodina and Tetramelas. Revisions of British and Irish Lichens 15: 1-35.
Text by Neil A Sanderson, based Cannon et al (2021)