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fleur-de-lis, horticultural iris, iris jaune, pale-yellow iris, yellow flag, yellow iris, yellow water iris

giant blue iris

Rhizomes

pink, freely branching, producing extensive clumps, 2–3 cm diam., with fibrous remains of old leaves;

roots fleshy.

green, extensively branched, forming large clumps, 2–4 cm diam., with pale leaf scars.

Stems

usually 1-branched, solid, 7–15 dm.

2–3-branched, solid, 10–15(–20+) 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.

basal 4–6, erect, blade bright green, ensiform, 10–13 dm × 2–3 cm, apex slightly curved;

cauline with blade foliaceous, appearing as elongated spathe, 5–6.5 dm × 2–3 cm, not exceeding flowers.

Inflorescence units

4–12-flowered;

spathes green with brown margins, outer spathe strongly keeled, inner without keel, 6–9 cm, subequal, margins not scarious.

2–3-flowered, branch units 1–2-flowered;

spathes tightly enclosing ovary and pedicel, 15–20 cm, subequal;

outer narrowly lanceolate, keeled, margins pale, narrow, inner margins translucent, broad, 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.

perianth blue or blue-purple;

floral tube tubular-prismatic, 9-ribbed and -grooved, 4–5 cm;

sepals blue or blue-purple with white streaks surrounding signal, oval to orbicular-oval, 9.5–11 × 4–5 cm, base abruptly attenuate into claw, apex obtusely angled, signal with raised, yellow, pubescent central ridge, claw green, striate, 4–4.5 × 1–1.2 cm;

petals erect or spreading-erect, spatulate, 7–8.5 × 2–3 cm, base cuneate, apex emarginate;

ovary bluntly 6-angled, 4–4.5 cm;

style blue-violet, keeled, 3.5–4 cm, raised above sepals, crests recurved, 1.5–2 cm, margins sharply and irregularly serrate;

stigmas 2-lobed with 2 triangular teeth;

pedicel columnar, 3.5–5 cm.

Capsules

prismatic to oblong-ovoid, obscurely 3-angled with obvious groove at each angle, 3.5–6 cm, beak 5 mm.

drooping, bright green, ellipsoid, hexagonal in cross section, with 6 broad, rounded lobes, 8–10 × 3 cm, indehiscent;

after anthesis, flower stem elongates, arching downward to push capsule into water, where walls are broken down and as funiculus is broken, seed rises to surface.

Seeds

D-shaped, flattened, 6–7 mm, corky, lustrous.

in 2 rows per locule, brown, D-shaped, 8–10 mm wide, very corky.

2n

= 34.

= 44.

Iris pseudacorus

Iris giganticaerulea

Phenology Flowering Apr–Jun. Flowering Mar–Apr.
Habitat Swamps, wet shores of rivers and lakes Shallow water or very wet roadside ditches
Distribution
from FNA
AL; AR; CA; DC; DE; FL; GA; IA; IL; IN; KS; KY; LA; MA; ME; MS; NC; NH; NY; OH; PA; RI; SC; TN; VA; WA; WV; BC; MB; NB; NF; NS; ON; PE; QC; Eurasia; n Africa [Introduced in North America]
[WildflowerSearch map]
[BONAP county map]
from FNA
AL; LA; MS
[WildflowerSearch map]
[BONAP county map]
Source FNA vol. 26, p. 390. FNA vol. 26.
Parent taxa Iridaceae > Iris > subg. Limniris > sect. Limniris > ser. Laevigatae Iridaceae > Iris > subg. Limniris > sect. Limniris > ser. Hexagonae
Sibling taxa
I. bracteata, I. brevicaulis, I. chrysophylla, I. cristata, I. douglasiana, I. fernaldii, I. fulva, I. germanica, I. giganticaerulea, I. hartwegii, I. hexagona, I. hookeri, I. innominata, I. lacustris, I. longipetala, I. macrosiphon, I. missouriensis, I. munzii, I. orientalis, I. pallida, I. prismatica, I. pumila, I. purdyi, I. savannarum, I. setosa, I. sibirica, I. tenax, I. tenuis, I. tenuissima, I. tridentata, I. verna, I. versicolor, I. virginica
I. bracteata, I. brevicaulis, I. chrysophylla, I. cristata, I. douglasiana, I. fernaldii, I. fulva, I. germanica, I. hartwegii, I. hexagona, I. hookeri, I. innominata, I. lacustris, I. longipetala, I. macrosiphon, I. missouriensis, I. munzii, I. orientalis, I. pallida, I. prismatica, I. pseudacorus, I. pumila, I. purdyi, I. savannarum, I. setosa, I. sibirica, I. tenax, I. tenuis, I. tenuissima, I. tridentata, I. verna, I. versicolor, I. virginica
Synonyms I. elephantina, I. hexagona var. giganticaerulea, I. miraculosa
Name authority Linnaeus: Sp. Pl. 1: 38. (1753) Small: Addisonia 14: 5, plate 451. (1929)
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