Tuesday, 1 January 2013

King Alfred's Cakes and Marble Galls

Daldinia concentrica
 New Year's Day. Waking up to brilliant sunshine I needed no persuading to go for a walk in Byfield's Pocket Park. Just inside the park an Ash tree was sporting a good number of King Alfred's Cakes. The growths are actually a fungus, Daldinia concentrica, and the name presumably refers to the fact that these hard structures look like burnt cakes. Their other name is Cramp Balls, stemming from a belief that, if carried in the pocket, they could prevent cramp. 

Oak Marble Galls

A little further on an oak bore several Marble Galls. These are quite different from Cramp Balls (which technically are not galls at all) and are caused by a gall wasp, Andricus kollari. The insect lays its eggs in a soft twig and, when an egg hatches, the grub begins to tunnel into the tissues; these respond by forming a gall in which the grub completes the first part of its life cycle. The insect, now bearing wings, tunnels out of the gall, leaving a hole. A couple of these are visible in my photograph. In fact the life cycle of gall wasps is usually very complicted and I do not intend to go into detail here. The study of plant galls, knows as cecidology, can greatly enhance a simple country walk.

No comments:

Post a Comment