what on earth is in our chicken run?

[nappychick]

OK, we have half a dozen of these in our chicken run down near the French Pyrenees. They are around where we feed, so could come from uneaten grain or from food thrown out by us or gite guests, or be from wild bird droppings, so origin totally unknown! They vary from waist to chest high and have a tuft of flowers at the top. The smaller plants have more side shoots than the tallest one. Leaves are huge, , up to almost two hands lengths, with a little spkey bit on the point. Shaped a bit like a long heart. Flowers small and dainty!
Any ideas?! We're fascinated now, and stymied!
Jac

[nappychick]

I have a response from Kew, copied below if anyone is interested! I have sent extra photos as requested, but this is a pretty good match anyway.
J
:)


"I'm sorry for the delay; your photographs have our experts slightly
baffled. From the first three photographs the plant would appear to
be a member of the knotweed family, and until recently would have
been referred to as a member of the genus Polygonum. It is
difficult to be certain from the photographs, but it would either have
been Polygonum orientale or a closely related species. Recently
however Polygonum has been split into several distinct genera, and
this species would now be known as Persicaria orientalis. It is
quite well known as an introduced weed in Europe.
However, they were rather puzzled by the spikes at the end of the
leaves - are they present on all the leaves or could they be as a
result of damage? Would it be possible to send additional close up
photographs of the leaves with these spikes from several different
angles?
Thank you."