In message
,
Dave Poole writes
Sacha wrote:
Any chance it could be R. Wedding Day escapee?

Sacha, I think the flowers are a bit too small and the clusters of
stamens not prominent enough for 'Wedding Day', although there's some
similarity. It is also very similar to a lot of species type
ramblers, but doesn't quite match many of those familiar to me. I
think chance seedling/garden escape is probably as close as we'll
get. It's a very nice thing to discover, I wonder what the hips are
like.

There were two plants growing on the east bank of a canal. The east bank
of the canal in this area is bordered by a line of fields lying between
the canal and a railway line, but this particular point is where a
corridor of woodland along a brook coming down from the ridge to the
east reaches the canal.

This is not a plausible location for a throwout, so I conclude that the
plants are "wild" (spontaneous).

Since all the suggestions are for members of section Synstylae, I
presume that we can take it that it is a member of this section. Apart
from the native Rosa arvensis, which this clearly isn't, three species
of this section are recorded from the wild in Britain - Rosa multiflora,
Rosa setigera and Rosa lucieae. Rosa setigera has fewer leaflets in a
leaf.

Rosa multiflora isn't exactly common in the wild (while I have 8 records
locally, one could probably question the wild status of all of them*),
but Rosa lucieae would be a first county record (and only has
half-a-dozen records this century). So it would seem to me that the
immediate question is whether Rosa multiflora can be eliminated. (And
does the number of flowers on an inflorescence eliminate Rosa lucieae
syn wichuraiana? - Stace says few-several.)

Looking at the figures in Stace all Synstylae hips look much the same -
except to experts.

In theory Rosa arvensis hybrids could complicate the issue.

*3 country parks, 3 urban canal side locations, an old railway line
converted to a footpath with a wide variety of species roses, and next
to a football ground.
--
Stewart Robert Hinsley