In message , Bob Hobden
writes
"Stewart Robert Hinsley" wrote

Perhaps a garden escape/throwout, as it's not readily recognisable as
a native species.

http://www.stewart.hinsley.me.uk/Images/Dicot68a.jpg

Original photo (large)

http://www.stewart.hinsley.me.uk/Images/IMG_6191.jpg


Not something I recognise as a garden pond plant. Could it be, like
some tropical plants, that it has different and quite different
immersed and emerged states.

You're sort of right. I've solved the identification myself, by looking
up a list of invasive aquatic plants. It's Ludwigia grandiflora
(water-primrose), which is heterophyllous, that latter leaves being much
narrower.

[The BSBI have 4 taxa of Ludwigia present in Britain, but the alternate
leaves identify this plant as Ludwigia grandiflora.]

-- Regards
Bob Hobden
Posting to this Newsgroup
from the W.of London. UK


--
Stewart Robert Hinsley