Bistorta major Gray
Syn. Persicaria bistorta (L.)Samp.; Polygonum bistorta L.
NO: Ormerot; ormrot
SE: Ormrot
DK: Slangeurt
FI: Konnantatar
DE: Schlangen-Knöterich
EN: Common Bistort
A perennial herb up to 1 m tall, B. major is native to Eurasia and nearly circumboreal in several races.It is an ancient medicine plant and also used as an ornamental species. In the Nordic countries it is mainly naturalised from garden escapes and usually occur on meadows and park lands. The terminal spikes with pink flowers are seen in June and July.
Plants photographed near Oslo, Norway 22 June 2013. This specimen was naturalised in open deciduous forest.

Image reference: BIST_MAJ_I1306223219_VIS.jpg
Visible light: Nikon D300, Medical-Nikkor 120 mm f/4 lens, built-in ring flash.

Image reference: BIST_MAJ_I13062241100_UV.jpg
Ultraviolet light: Nikon D600, UV-Nikkor 105 mm f/4.5 lens, Baader U2" (Venus) filter, Broncolor studio flashes (uncoated Xenon tube), 37 frames stacked in Zerene Stacker.
The perianth of B. major is covered with low conical cells making iridescence likely.
References:
http://www.ultraviol...ure-references/
[Published 23 June 2013]