Yellow Flag Iris
Iris pseudacorus
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Almost certainly the flower behind the fleur-de-lis.
A tall, robust waterside perennial with stiff, upright, sword-shaped grey-green leaves and large bright yellow flowers marked with darker veining on the drooping outer petals. Yellow flag grows in marshes, ditches, pond and loch margins and wet meadows around Dumfries, often forming extensive stands.
Behaviour
It spreads by thick creeping rhizomes as well as by large corky floating seeds, which is how it colonises along a watercourse. The flower is structured so that a visiting bumblebee is funnelled under the style and forced past the anthers. The species is widely used in reedbeds and constructed wetlands because the rhizomes take up metals and nutrients from polluted water.
When to see it
Quick facts
- Family
- Irises (Iridaceae)
- Height
- 40–150 cm
- Status
- Native; common at water margins
Photo by Myrabella, CC BY-SA 3.0, via Wikimedia Commons