Lichens on trees and twigs in St Andrews Park Nov 2010
Pick up any fallen twig and you could see some of the beautiful lichens that live in the park. You will need a magnifying glass to see the detail, but you should be able to match your lichen to one of these…..
Thanks to the website masters who have allowed us to use their excellent photos to illustrate these lichens. Like any branch of science, there are some technical terms; you can find out more at
Xanthoria parietina. A bright orange lichen when dry, it is quite green when wet, as it often is on the trees in the park. It also common on roofs under bird-perching sites, for example the TV aerials, so that the roof looks golden from a distance. It is very resistant to air pollution.
Physcia aipiola. A compact blue-green lichen with distinct white flecks (pseudocyphellae) on the surface. Usually fertile with large round dark apothecia. Common on twigs and tree bark. Returning to towns as pollution levels drop.
Physcia tenella Small whiskery lichen on twigs.
Hyperphyscia adglutinata. Bright green. Lobed, adpressed, narrow thallus below dense clusters of soredia. Lots of it on bases of the Plane trees. Often found on sites enriched by dust.
Punctelia jeckeri (P. ulophylla) Green-grey when fresh it becomes pale grey when dry. Widespread on a avariety of trees.
Melanelixia fuliginosa subsp glabrulata. (Parmelia glabratula)Green shiny with obvious isidia (small upright ‘soldiers’ on the surface) on fallen twig.
Parmelia sulcata on a fallen branch. Grey with marginal and laminal soralia from faint reticulum. Underside pale brown at edges, centre black. Simple and squarrose rhizinae.
Physcia adscendens very common, found in the park on trees and elsewhere on calcareous rocks and tombstones.
Parmelia saxalitilis. This lichen grows on rocks (as its name suggests) and trees. Specimens growing on human bones used to be considered to have medicinal properties. It was also used to produce a reddish brown dye.
Evernia prunastri is a different from most other lichens in the park, as it is bushy rather than flat on the branches.
In places where there is little pollution, away from towns, trees may be festooned with hanging fruticose lichens.
If we saw our park trees like this, we would be surprised, but very pleased.
Lecanora chlarotera. Lichens which adhere very closely to the surface of the branch or stone are called ‘crustose’. You may not have even realised that these roundish marks with coloured dots are lichens.
L chlarotera is often found with Lecidella elaeochroma
Porina aenea. Small black perithecia on green-brown crustose thallus in oval patches on fallen twig.
Lecanora symmicta. Some of the lichens look a bit like each other.
Initially I thought this was L confusa, but the latter has a smooth thallus.
The apothecia seem like L. confusa in being crenulate but persistent so far…… No decision yet; that’s how it sometimes is in science.
A
nd then there all the ones that grow on walls, rocks, tombstones and pathways.
Lecanora muralis. This one, for instance, looks a bit like chewing gum; but look more closely……..