pale yellow iris, yellow flag iris

Iris pseudacorus L.

Description from Invasive.org

Appearance
Iris pseudacorus is a herbaceous perennial that can grow up to 3-4 ft. (0.9-1.2 m) in height.
Foliage
Broad, sword-shaped leaves are stiff, erect and glaucous. They measure between 1.6-3.3 ft. (0.5-1 m) long and 0.4-1.2 in. (1-3 cm) wide. Rhizomes are pink-fleshed and 0.4-1.6 in. (1-4 cm) in diameter.
Flowers
Flowers are showy and bloom from April to June. Usually yellow, their color can range from nearly white to cream. Flowers are 2.75-3.5 in. (7-9 cm) wide. They are borne on erect peduncles with several flowers per stem. There are six perianth clawed segments. Three of these are upward-pointing petals and three are down-ward spreading sepals. Sepals often have purple, brown or red veins on their yellow surface.
Fruit
Fruits are 1.6-2.7 in. (4-8 cm) long capsules. The capsules are 6-angled and cylindric-prismatic to ellipsoid. The average capsule contains about 120 white seeds that harden and turn brown as they mature.
Ecological Threat
It forms large clonal colonies displacing native species. The rhizomes are able to survive heavy droughts. Rhizomes and seeds can be transported downstream, further spreading the plant. Seeds can germinate even after a wetland area burns. It contains glycosides, making it toxic to grazing animals. No birds are known to disperse the seeds of this plant. Caution should be used when hand-pulling, as it can cause skin irritation.

Resources


Selected Images from Invasive.org

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Plant(s) in flower
Todd Pfeiffer, Klamath County Weed Control, Bugwood.org
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Flower(s)
Nancy Loewenstein, Auburn University, Bugwood.org
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Flower(s)
Nancy Loewenstein, Auburn University, Bugwood.org
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Fruit(s) fruit.
Joseph M. DiTomaso, University of California - Davis, Bugwood.org
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Flower(s) pale yellow form
Leslie J. Mehrhoff, University of Connecticut, Bugwood.org
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Flower(s)
Nancy Loewenstein, Auburn University, Bugwood.org
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Fruit(s)
Leslie J. Mehrhoff, University of Connecticut, Bugwood.org
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Plant(s) along drainage area
Nancy Loewenstein, Auburn University, Bugwood.org
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Plant(s) along drainage area
Nancy Loewenstein, Auburn University, Bugwood.org
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Infestation
Leslie J. Mehrhoff, University of Connecticut, Bugwood.org
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Seed(s)
Leslie J. Mehrhoff, University of Connecticut, Bugwood.org
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Seed(s)
Steve Hurst, USDA NRCS PLANTS Database, Bugwood.org
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Root(s) Inside of cut rhizome
Leslie J. Mehrhoff, University of Connecticut, Bugwood.org
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Root(s) large rhizome.
Joseph M. DiTomaso, University of California - Davis, Bugwood.org
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Plant(s)
Leslie J. Mehrhoff, University of Connecticut, Bugwood.org
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Plant(s) Britton, N.L., and A. Brown. 1913. Illustrated flora of the northern states and Canada. Vol. 1: 540.
USDA NRCS PLANTS Database , USDA NRCS PLANTS Database, Bugwood.org
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Plant(s) USDA NRCS. Wetland flora: Field office illustrated guide to plant species. USDA Natural Resources Conservation Service.
USDA NRCS PLANTS Database , USDA NRCS PLANTS Database, Bugwood.org
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Distribution