Calicium notarisii
Thallus greenish yellow, spreading more or less radially, and reaching up to 10 cm; forming discontinuous patches, and appearing like small warts grouped together. Across section the cortex is up to 35 µm thick, with a thinner hyaline layer on top, but the lower part densely interspersed with crystals. Photobiont, located in a layer below the cortex, consists of chlorococcoid algae, 10-15 µm diam, possibly a species of Trebouxia.
Anamorph: Pycnidial, black 50-100 µm diam, but usually forming irregular clusters up to 0.25 mm wide, which open by a longitudinal slit. Pycnidial wall consisting of thick walled isodiametric cells, never surpassing 5 µm in diam. Conidiogenous cells hyaline and ampulliform producing aseptate and colourless conidia which can be bacilliform to narrowly ellipsoidal, ca 4 x 1.5-2 µm.
Teleomorph: Ascomata non pruinose apothecia, mostly 200-350 µm wide, black, and immersed in thallus warts which can be up to a millimetre across, and appear ‘lecanorine’. Exciple black and thin throughout, even at the base, up to 35 µm wide, formed by dark, thick-walled, and interwoven hyphae. Hypothecium very thin, unpigmented. Asci clavate at first, but becoming obpyriform and soon evanescent, 15- 20 (-27) x 4-7 (-10) µm, octospored. Ascospores dispersed passively and synchronously (a mazaedium), and continue to mature once the ascus dissolves to become sub-muriform, (13-) 20-30 (-33) x (11-) 14-20 µm, broadly ellipsoidal, brown, with smooth, thick walls; the number of septa in the ascospores vary from one to seven, and septum formation starts with 1- transversal division, followed by longitudinal and/or oblique ones.
Chemistry: The thallus contains rhizocarpic acid, which is a tetronic/pulvinic acid derivative, but this cannot be detected by spot tests using K, C, KC or Pd, only by chromatography. This acid provides the distinctive greenish yellow colour of the lichen.
Assessed in Britain by Woods & Coppins (2012) as Near Threatened and Nationally Scarce; IUCN status in Europe: Rare.
Calicium (Cyphelium) notarisii can be confused with the closely related C. tigillare because both have a yellowish-green thallus, sessile-immersed apothecia, and present a mazaedium; i.e. the spores can be noted when brushing your finger tip over the ascomata, by the soot-like residue left behind. C. notarisii however can be separated microscopically from C. tigillare and other congeneric species in ascospore morphology: it is the only species with sessile ascomata in which the ascospores are multicellular not just bicellular.
The species is so far known from temperate regions of the Northern Hemisphere (Tibell 1994). In Great Britain it is present in England (counties of Yorkshire, Norfolk, Suffolk, Essex, Kent, Sussex, Hampshire, Dorset & Surrey) and Wales (Caernarvonshire), usually occurring in localities not far from the coast. It is probably dispersed by humans and livestock rubbing against the substrate where it grows (Dobson 2003). In continental Europe, and particularly in Southern countries, it is found in mountain habitats. BLS map here.
The species was first described in the nineteenth century from the bark of pine trunks, but currently it is more common on (acidic) wood, used for fence railings, telegraph posts, benches, barns and other human dwellings. In Britain it prefers well-lit open dust impregnated habitats, often near water and/or coastal areas, and is a pioneer species of sawn wood, though it is only present in well weathered old wood. The lichens Amandinea punctata and Lecanora conizaeoides are usually found accompanying Calicium notarisii.
In Sweden, like in Britain, the lichen preferred man-made wooden structures, but other reports from continental Europe showed the lichen could be found on bark or wood of native forests of conifers and oaks (Hawksworth 2004, Muñiz & Hladun 2011), with potential as bio-indicator species of forest continuity and traditional forest management regimes.