Looking for Lichens

We were absolutely delighted to be invited to explore Petersfield Heath and Pond in the company of Petersfield Area Lichen Enthusiasts (PALE). This area covers some 69 acres of land together with a 22 acre pond and has a range of woodland, scrub and heathland habitat with a wide variety of lichens. There was obviously a lot of other flora and fauna to see and it might be that another field trip beckons to look at the wider natural history of the patch.

But today was about lichens. And cake, but more of that later.

Peter Bisset met us at the Plump Duck cafe and after a brief introduction to the area and what we might see we set off for a three hour wander around this clearly popular, but not crowded, public space. Apart from Phil Budd, we were all pretty much lichen novices, so there was a lot new to see but one good thing was, unlike the natural history we are perhaps more familiar with, the lichens stayed put – often for many, many years.

I won’t attempt here to give names to all the 40 or so species we saw – please feel free to attempt your own identification from the images shown below. But there are three species that are worthy of more of a mention.

The Tree Phaeographis (Phaeographis dendritica) is found on a range of deciduous trees including Hornbeam, Oak and Beech. Remarkably Peter found this specimen whilst hurrying over the heath because the colour of this lichen – about 5cm across – stood out from all the other pale lichens. You clearly have to get your eye in!! But this is one of the Graphis lichens which all seem to resemble varieties of cuneiform writing, although Peter felt the rather diagnostic shape here was more reminiscent of ships ploughing a wake through the sea.

Lichens are made up of two or more different organisms living together, a fungus and an alga. The fungus provides the body (thallus) in which the algal partner can live, protected from damaging conditions such as high levels of light (ultraviolet radiation) and lack of water (drought). The algal partner provides the essential carbohydrates (food for the fungus) from carbon dioxide and water, with the aid of sunlight. This close, interdependent relationship is referred to as a symbiosis.

Unlike mosses and flowering plants, lichens do not have green leaves or a stem. They may be pale or bright coloured and commonly occur in three forms: Leafy or Foliose, with leaf like lobes, loosely attached to the tree or other substrate; Bushy or Fruticose, coral-like branched and tree or bush-like, usually with a single attachment; and Crust-like or Crustose, closely attached as though pressed on.

With over 1,800 species of lichen in the UK identification is not always straightforward, and microscopic examination or even testing with chemical solutions or UV light may be necessary. But fortunately you don’t need to identify the exact species to enjoy its beauty. And occasionally even the difficult groups helpfully have some diagnostic feature which can be picked out with a hand-lens or good quality photograph, or even with the naked eye.

The ‘pins’ – small upward-pointing fruiting bodies supposed to resemble dressmakers’ pins – of this particular lichen help identify it as Chaenotheca ferruginea which is found on dry bark crevices of deciduous trees or old conifers.

The third lichen to highlight is almost a star in its own right in Petersfield. From the Petersfield Post in April of this year:

The Petersfield Area Lichen Enthusiasts (PALE) discovered a rarity on Petersfield Heath one cold morning earlier this year.

The unusual lichen – Teloschistes chrysopthalamus – was thought to be almost extinct in the British Isles. This is a Mediterranean lichen whose last known substantial sighting was back in the 1960s on old, outgrown orchard trees in Herefordshire.

Since then the occasional record has been made of Teloschistes along the south coast, in Cornwall and the Isles of Scilly, but this would be one of the first inland records – and, certainly, the most northerly.

A single specimen was found a year or two ago on Peartree Green LNR in Southampton, so this was a brilliant link between our two groups and a highlight of our visit. Subsequently PALE have found more locations for Teloschistes chrysopthalamus on Hawthorn and Blackthorn across the crest of the Downs. The Petersfield Heath record on Oak, however, remains an unusual record for the UK (although not unknown in France).

If you get a chance this is a site well worth a look, for lichens and other flora and fauna.

So thank you to PALE for showing us round some of the lichens of the area, including your local celebrity Golden Eye lichen. And a real thank you to Peter’s wife, who had been staffing a cake stall a local fayre and arrived hot foot to refuel us with a range of gorgeous cakes and savoury items.

Finally a few more images for you to enjoy.