Bistort (Common Bistort, Alpine Bistort)

Bistort is a member of the Polygonaceae family where many members contain oxalic acid which binds with calcium, thus preventing absorption.  It is also a diuretic so best avoided.

Although a wild flower, some species of Bistort are cultivated for the garden and in addition to the more common pink shades, the flowers can also be found in white.  See also Knotweed and Persicaria and Red Bistort.