Mike Lyle wrote:
I think the English is just an adaptation of late Latin _branca_, "paw".
"Brank[s]" for "scold's bridle" is a Scots word of unestablished origin.
In English English "Brank" was also used for buckwheat, but I don't
think there's a connection there.

You perhaps missed my post on this ...

From the folklore of plants .... "The bear is another common prefix.
Thus there is the bear's-foot, from its digital leaf, the bear-berry,
or bear's-bilberry, from its fruit being a favourite food of bears, and
the bear's-garlick. There is the bear's-breech, from its roughness, a
name transferred by some mistake from the Acanthus to the cow-parsnip,
and the bear's-wort, which it has been suggested "is rather to be
derived from its use in uterine complaints than from the animal."

My book 'naming of plants' says the acanthus is called bear's breech
from the size and appearance of the leaf which is very big, broad and
hairy. Acanthus in greek means thorn.