Cyphelium notarisii (soot lichen)

Recorded from temperate regions of the Northern Hemisphere, with voucher material confirmed from Europe and North America. Cyphelium notarisii is probably dispersed by humans and livestock rubbing against the substrate where it grows. In Great Britain C. notarisii usually occurs near the coast, whereas in continental Europe it is found in montane habitats, particularly in southern countries.

This rare lichen forms greenish-yellow crusts on wooden structures and has small, black, disc-like fruitbodies. It can be distinguished from similar lichens by the sooty residue left on your finger after rubbing the fruitbodies. This is also a distinctive feature of related lichen genera in the family Caliciaceae, commonly known as pin lichens.

Images: Close ups of Cyphelium notarisii taken with a stereo microscope; left: magnified 50 times; right: magnified 630 times (Images: Begoña Aguirre-Hudson)

The greenish-yellow thallus of Cyphelium notarisii can be several centimetres long, usually spreading more or less radially. It is not continuous, but broken into small lumps, which look like small warts grouped together, and is sometimes patchy when the thallus disappears below the substrate. The discoidal fruiting bodies (apothecia) are less than a millimetre across, black and immersed in the thallus warts. This latter feature separates species in the genus Cyphelium from the closely related pin lichens, where the apothecia are mostly stalked. However, recent research completed at Kew revealed that this character alone cannot reliably distinguish between these lichen groups. The researchers found a sessile (without a stalk) pin lichen, Calicium victorianum, new to Europe, and previously only known from Eucalyptus woods in the Southern Hemisphere.

The reproductive cells, or spores, of Cyphelium notarisii are formed inside a sac (ascus) and are dispersed passively, all the sacs maturing and disintegrating at the same time (a mazaedium). The spores are ellipsoidal, brown and multicellular due to irregular septation of the cell wall (sub-muriform), the number of septa varying from one to seven. This spore shape and septation can only be seen under the microscope, as the ascospores do not exceed 30 µm in length. However, the spores can be seen as a soot-like residue after brushing your finger tip over the fruitbodies.

A thorough investigation in Sweden found Cyphelium notarisii to be more common on older buildings and other wooden structures, which had not been maintained in a while; but it can tolerate thin layers of traditional paint. In other reports from continental Europe, C. notarisii has been found on bark or wood in native forests, and like some species of pin lichen is probably a bio-indicator of forest continuity and traditional forest management regimes.

In Britain C. notarisii has been reported as a pioneer species of sawn wood, and also as only present on well-weathered, old wood. The disappearance of this species from the original bench where it was found near the Waterlily House at Kew, and the presence of new populations, require further investigation and monitoring in the Gardens.

No uses have been reported for Cyphelium notarisii. The thallus contains rhizocarpic acid, which is a pulvinic acid derivative. This acid provides the distinctive greenish-yellow colour of the main body of the lichen

Cyphelium notarisii on a bench between the Palm House and Palm House pond at Kew Gardens (Image: Begoña Aguirre-Hudson)

Cyphelium notarisii can be seen on a few wooden benches between the Palm House and the Palm House Pond (amongst the Queens’s Beasts sculptures). Here it can be observed growing alongside the lichens Amandinea punctata, Candellariella vitelina and Lecanora conizaeoides, the latter parasitised by the pink-coloured fungus Marchandiomyces corallinus, which is more obvious in the winter. Interestingly, A. punctata and L. conizaeoides were also found accompanying C.notarisii when it was first reported in Britain, following collection from Minster Marshes in Kent.

In addition to the lichens found growing in situ, two voucher specimens are kept in the fungal reference collection, both collected from the Gardens at Kew. The dry collection of fungi (Kew’s Fungarium) also holds four other species of the genus Cyphelium. Of these, only C. tigillare - represented by two historical vouchers in the Borrer Herbarium (within Kew's Herbarium) - is also of conservation concern. C. notarisii and C. tigillare can be separated at microscopic level by the morphology of the spores, but molecularly they are very closely related, and can be confused by the naked eye. These dried specimens can be studied by appointment with the curator of the fungarium.

A fourth site for Cyphelium notarisii in Spain – David Hawksworth (2004).

National Biodiversity Network – NBN Gateway – Grid map of records for Cyphelium notarisii.

The Mycology science team at Kew

About the fungi kingdom