black bryony

this rather magnificent climber is black bryony, the only native member of the yam family. It climbs by curling invariably in a clockwise direction (how does nature do this?). It is much more prominent in the autumn when it is covered in bright berries of varying hues (see bottom photo), but I have never seen it in flower before. I think the reason is that the little 6 petalled green-ish flowers are very inconspicuous.