Elder and Lichens

Lichens are just about the most colourful objects in the landscape hereabouts at this time of year. This one is a Xanthoria species - Xanthoria parietina I think - growing on an elder twig. The little orange discs are apothecia, which produce the spores from the fungal component of the symbiotic relationship between the alga and fungus that constitutes a lichen.

Old elders (is that a tautology?) are often smothered with this yellow lichen, bringing the whole tree to life when it's lit by winter sunshine. X.parietina thrives in sites where there is plenty of nitrogen in the substrate, such as tree branches where birds have perched and left droppings.

Older Elder

Most elders Sambucus nigra growing in hedgerows never achieve much more than large shrub-size and are usually short-lived, but when this species does have space to grow it can become quite a handsome tree, with deeply fissured bark on its trunk. This individual (double-click for a larger image) grows beside the road between the Derwent reservoir and Blanchland and like many mature elders it's playing host to a dense covering of lichens on its branches and twigs, that look very attractive in the spring sunlight.

The yellow lichen is a Xanthoria species - probably Xanthoria polycarpa - that forms a dense covering on most of the older elder twigs.

Elder seems to be favoured host for this lichen - most trees seem to have some and many are smothered in it. I wonder what it is about elder bark that that makes it a favoured host?

For more posts on tree ID click here