Iris pseudacorus L.
  • Sp. Pl. : 38 (1753)
  • Levers

Cite taxon page as 'WFO (2023): Iris pseudacorus L. Published on the Internet; Accessed on: 05 Jun 2023'

General Information

Rhizomes pink, freely branching, producing extensive clumps, 2–3 cm diam., with fibrous remains of old leaves; roots fleshy. Stems usually 1-branched, solid, 7–15 dm. Leaves: basal deciduous, at first erect, then recurved, blade dark green, with prominent median thickening, 4–10 dm × 2–3 cm, slightly glaucous basally; cauline equaling inflorescence unit. Inflorescence units 4–12-flowered; spathes green with brown margins, outer spathe strongly keeled, inner without keel, 6–9 cm, subequal, margins not scarious. Flowers: perianth bright yellow; floral tube 0.6–0.8 cm, with no constriction into ovary; sepals bright yellow or cream colored, lanceolate to ovate or suborbiculate, 5–7.5 × 3–4 cm, base abruptly attenuate, claw ca. 1/2 length of limb, signal a darker yellow basal patch limited by short, brown lines; petals without veining, lanceolate to spatulate, 2–3 cm; ovary triangular in cross section with concave sides and narrow groove at each angle, 1.5 cm; style keeled, 3–4 cm, crests spreading, 1–1.2 cm, laciniate at apex; stigmas rounded with prominent tongue; pedicel 2.5–7 cm. Capsules prismatic to oblong-ovoid, obscurely 3-angled with obvious groove at each angle, 3.5–6 cm, beak 5 mm. Seeds D-shaped, flattened, 6–7 mm, corky, lustrous. 2n = 34.

  • Provided by: [B].Flora of North America @
    • Source: [
    • 2
    • ]. 

    Lvs stiff and erect, broadly ensiform from densely crowded rhizomes; stem 0.5–1 m, shorter than or equaling the lvs; fls 7–9 cm wide, bright yellow or cream-color; sep spreading, the crest area outlined by an irregular series of brown markings; pet erect, ligulate, constricted at the middle, 1–2.5 cm, unmarked; capsule 6-angled, cylindric-prismatic to ellipsoid, 5–8.5 cm, the valves widely spreading at maturity; 2n=24–34. Swamps and shallow water along streams and ponds; native of Europe, and widely established in our range. Apr.–June.

  • Provided by: [F].Manual of Vascular Plants of Northeastern US and Canada
    • Source: [
    • 4
    • ]. 


    Stem: subterranean . Leaf: phylotaxy ; form . Inflorescence: number flower multiflorous. Flower: tepal(s) ; colour ; fusion tepal(s) ; style . Seed: aril ; colour .

  • Provided by: [A].Brazilian Flora 2020 project - Projeto Flora do Brasil 2020
    • Source: [
    • 1
    • ]. 

    Tallo: subterraneo(s) . Hoja: filotaxia ; forma . Inflorescencia: número flor(es) multiflora(s). Flor: tépala(s) ; color ; fusión tépala(s) ; estilo(s) . Semilla: arilo(s) ; color .

  • Provided by: [A].Brazilian Flora 2020 project - Projeto Flora do Brasil 2020
    • Source: [
    • 1
    • ]. 

    Caule: subterrâneo(s) . Folha: filotaxia ; forma . Inflorescência: número flor(es) multiflora(s). Flor: tépala(s) ; cor ; fusão tépala(s) ; estilete(s) . Semente: arilo(s) ; cor .

  • Provided by: [A].Brazilian Flora 2020 project - Projeto Flora do Brasil 2020
    • Source: [
    • 1
    • ]. 

    Stängel 50–100 cm hoch, etwas zusammengedrückt. Blätter lineal, 1–3 cm breit und bis 90 cm lang, mit starker Mittelrippe, allmählich zugespitzt, 2zeilig angeordnet, die meisten grundständig. Blütenstand 4–12blütig, Blüten gelb. Die 3 äussere

  • Provided by: [C].Flora Helvetica – Illustrierte Flora der Schweiz
    • Source: [
    • 3
    • ]. 


    6. Ufer, Röhricht, Gräben, kollin(-montan). J, M, AN, südliches TI, VS (Rhonetal).

  • Provided by: [C].Flora Helvetica – Illustrierte Flora der Schweiz
    • Source: [
    • 3
    • ]. 

    Distribution Map

    • Native distribution
    Found in
    • Europe Northern Europe Ireland

    Nationally Preferred Names

    Yellow flagEnglishIE

    Other Local Names

    Giaggiolo acquaticoItalianCH
    wild irisEnglishIE
    Marsh flagEnglishIE
    Yellow irisEnglishIE
    the May flowerEnglishIE
    Iris jauneFrenchCH
    Gelbe SchwertlilieGermanCH
    Iris melnaRaeto-RomanceCH
    Yellow iris, pale-yellow iris, yellow flag, yellow water iris, fleur-de-lis, iris jaune
    Eileastar (or Eileastrom or Eileastron)IrishIE


     Information From

    Brazilian Flora 2020 project - Projeto Flora do Brasil 2020
    The Brazilian Flora Group (2018): Brazilian Flora 2020. Dataset/Checklist:
    • A Group Brazil Flora, REFLORA Program
    Flora of North America @
    'Flora of North America @ eFloras (2008). Published on the Internet [accessed August 2016]' Missouri Botanical Garden, St. Louis, MO & Harvard University Herbaria, Cambridge, MA.
    • B Flora of North America Association
    Flora Helvetica – Illustrierte Flora der Schweiz
    Flora Helvetica – Illustrierte Flora der Schweiz, Konrad Lauber, Gerhart Wagner, Andreas Gygax. Haupt Verlag 2018.
    • C All Rights Reserved
    World Flora Online Data. 2021.
    • D CC0 1.0 Universal (CC0 1.0).
    World Flora Online Data. 2021.
    • E CC0 1.0 Universal (CC0 1.0).
    Manual of Vascular Plants of Northeastern US and Canada
    Descriptions of plants should be attributed to the full citation for each individual article, chapter or book that is the source for each record, which should include the authors of original publication.
    • F Content licensed under Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported License
    Irish Vernacular Names
    • G All Rights Reserved
    World Flora Online Consortium
    World Flora Online Data. 2017.
    • H CC0 1.0 Universal (CC0 1.0).