I.D Which Bindweed please

[Johnny81]

Sorry to hijack the thread but I just read this and completely forgetting there are large and Hedge Bindweed I went in my garden to have a look for my own learning and am still confused, so I posted what I have just taken in my garden.


The bracts are slightly covering here but is an opening... confused! Which is this?

[AlanS]

Originally Posted by Johnny81

Sorry to hijack the thread but I just read this and completely forgetting there are large and Hedge Bindweed I went in my garden to have a look for my own learning and am still confused, so I posted what I have just taken in my garden.


The bracts are slightly covering here but is an opening... confused! Which is this?

Hello Johnny, far from hijacking the thread, you are helping it with a very useful photograph.

This is Large Bindweed (Calystegia silvatica), but as I said above, we have two subspecies of it in Britain, both widespread.
Your photograph is of C. silvatica subsp. disjuncta. The two bracteoles overlap and enclose the base of the flower. Inside the bracteoles we have the calyx, also green, and at the point of overlap of the bracteoles, we do see some of the calyx exposed. The backs of the bracteoles, from the tip to where they suddenly curve towards the flower-stalk, pretty much follow a straight line.

If this was C. silvatica subsp. silvatica, the bracteoles would be larger and relatively much wider in side view, would usually completely hide the calyx, and appear more inflated, i.e. they are distinctly convex along the line from the tip of the bracteole to where they curve at the base.

In Hedge Bindweed (Calystegia sepium), the bracteoles are folded or slightly inflated, or even remain as 2-dimensional leaf-like flaps, and do not overlap.

Flower size is largest in C. silvatica subsp. silvatica, smallest in C. sepium, but not much use for identification on its own.


The distributions of the two subspecies are not well known yet. C. silvatica subsp. disjuncta is generally distributed and locally common. In my own experience, C. silvatica subsp. silvatica is locally very common in parts of southern England, but it is said to be more western overall.
C. sepium is, of course, our native plant and generally common thoughout lowland Britain.

Undoubtedly, for people familiar with subsp. silvatica, with its big, very inflated bracteoles, plants such as photographed by Johnny are puzzling if they don't know of the second subspecies.

There are diagrams and more information in the 'Plant Crib 1998', published by the B.S.B.I.


Now let's hope nobody posts any photographs of pink-flowered Calystegia, because they get difficult ....

Alan

[stevecurtis]

Please interrupt away thanks for joinning in ,has anyone got a simular photo of hedge bindweed.

all the best steve