Thursday, 21 September 2017

Loddon pondweed... IN THE THAMES!

I do not use capital letters lightly: the rediscovery of Potamogeton nodosus, the so-called Loddon pondweed, in the River Thames is really very big botanical news indeed! Otherwise known only from the River Loddon, the Bristol Avon and the Dorset Stour, this very rare pondweed was thought to have gone extinct in the Thames in the 1950s and there have been no Oxfordshire records for over 75 years. It was found by Frank Hunt back in August, near Marsh Lock, just south of Henley (SU774815), growing in a part of the river sheltered from boat traffic by a footbridge. Marsh Lock is less than 1km downstream from where it was seen by J.E. Lousley in 1941 and about 5km below where the Loddon joins the Thames. Frank also tells me that there is a patch in the the Berkshire part of the river too.

This is such a distinctive species that the referee for pondweeds, Dr Chris Preston, was quite happy to verify the record from the photograph shown right (and attributable to Frank).

1 comment:

  1. Well, seems Potamogeton nodosus has been recorded in the Thames in Berks and Bucks recently but the records have not made it to the database for whatever reason. However, the record is still a significant rediscovery for Oxon.

    I suppose this kind of thing highlights the importance of sharing data - among the many reasons it may prevent people from get carried away on social media!