Star Jelly and Ramshorns

In a friend's garden earlier today, I saw something glistening in a very damp lawn and was pleased to see that it was a slime mould; to be more precise it was Nostoc commune. This is not a rare species (and can be a problem for anyone wanting a bowling-green for a lawn) but, with its green-brown coloration, it is easily overlooked.

Nostoc commune in a lawn at Aston le Walls,
Northamptonshire. 23 October, 2013

In Northamptonshire it was once known as "Star Jelly" from the belief that it grew where a shooting star had hit the earth. A great deal of folk lore is attached to this strange organism. It is technically a cyanobacterium and I have no intention of going into details of its peculiar life; anyone thirsting for details can easily find these from a plethora of web-sites.

The first British reference to it apparently dates the 15th century, when it was recorded from Cornwall. It was referred to as "sterre-slyme" (star-slime) so, even then, a belief prevailed that it was associated with shooting stars. In dry conditions it takes on the appearance if a small piece of dry seaweed, but with the coming of rain it can swell quite rapidly.

Earlier in the day I was pleased to spot a Ramshorn Gall on an oak tree in Byfield Pocket Park. Whereas the Star Jelly has been known since 1440, this gall it has only been known in Britain since 1997. It too is easily overlooked, especially when it has become dry - as was the case with my specimen. Like many galls on oak trees, it was caused by a cynipid wasp, in this case Andricus aries. Since being first found near Maidenhead it has spread at remarkable speed through Britain and by 2010 had been found as far north as Perthshire, Scotland.

Ramshorn Gall caused by the wasp
Andricus aries. Byfield Pocket Park 23 October, 2013

A number of gall wasps are spreading north and west across Europe and many are finding their way into Britain so we may expect more 'invasions' like this in the future.