Sunday 6 February 2011

Lichens on Hayes Common

Ishpi Blatchley (second from rght) addressing a group on lichen heathland in Hayes Common
Ishpi Blatchley (second from rght) addressing a group
On 23 January, a Sunday, Ishpi Blatchley led a walk on Hayes Common to introduce us to lichens. It was cold; very cold and windy.

We started in the woods where there was some shelter, but when we got to the open heathland shown in the photo, there was less enthusiasm. Ishpi knows lots about lichens (and bats) and I would certainly have benefited more if I had dressed for standing around rather than for walking.
Cladonia species on lichen heathland on Hayes Common
Cladonia species on lichen heathland on Hayes Common

There were plenty of lichens all around us. The more you know, the more you see, and with lichens it's amazing how much more you can see with a magnifying lens. The apothecia, fruiting structures that Ishpi called jam tarts, were quite vivid in their various colours. Right, Cladonia on the heath; below, some Xanthoria with apothecia from a nearby wall. That wall was next to a road, and you can see bits of road dirt all over the lichen; this species is more resistant to pollution than most.

One thing Ishpi mentioned but couldn't show us is that some crustose lichens on trees seem to grow in elongated bands rather than circles. This is because the trunk of a young tree expands faster than the lichen can grow, and drags it out sideways! And I saw some good examples of this another day, on the Beech Walk at High Elms.
Xanthoria species with apothecia on a wall in Hayes
Xanthoria species with apothecia on a wall in Hayes

Sarah Adams of Bromley Countryside Services was also there, and showed us examples of the small and delicate Dwarf Gorse among the large and sturdy European Gorse. And there were a couple of people who knew some local history, who told us that the area which became the heath had been scraped and flattened for anti-aircraft gun emplacements in World War II, and that some temporary housing at around the same time accounted for the apple trees that grow at the Keston end of the common. Some of those apples are very tasty.

In fact, when I went to check some of this out on line, I found a leaflet - the Ravensbourne Trail - with these facts and more ... so perhaps Local Knowledge Man was actually Read The Leaflet Man.

The heath isn't signposted, so if you should find yourself on it, watch out for the poisonous adders.

Added below, later: more and healthier Xanthoria on another local wall, with apothecia just beginning to develop; and another species, which I know we saw on the walk but the name of which I can't remember ...

Xanthoria species with another lichen on a wall in Hayes
Xanthoria species with another lichen on a wall in Hayes

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