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giant blue iris

yellowband iris

Rhizomes

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

sparingly short-branched, forming dense clumps, 1–1.5 cm diam., hard, with old leaf bases at nodes;

roots fleshy.

Stems

2–3-branched, solid, 10–15(–20+) dm.

slightly flattened, with 1–2 short branches, solid, 4–12 dm.

Leaves

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.

basal erect, blade with slight spiral twist and central ridge, 3.5–8 dm × 1–2 cm, stiff, harsh, fibrous, glaucous;

cauline 2–3, 1–2 subtending floral clusters, blade reduced.

Inflorescence units

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.

clustered, 2–4-flowered;

spathes white, 3–5 cm, subequal, papery.

Flowers

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.

perianth white;

floral tube funnelform, 1–2.5 cm;

sepals spreading and arching downward, with large yellow basal area, broadly orbicular, 8–10 × 3–6 cm, apex rounded, deeply emarginate;

petals white, spatulate, 4–6 × 1–1.5 cm, base gradually attenuate, apex emarginate;

ovary triangular in cross section with 2 ribs at each angle, 2–2.5 cm;

style white, with parallel sides, 4–5 cm, crests erect, triangular, 1–2 cm;

stigmas 2-lobed;

pedicel 2.5–7.5 cm.

Capsules

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.

ovoid to oblong-elliptic, triangular in cross section, each angle 2-ribbed, 4–5 × 2–2.5 cm.

Seeds

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

in 2 rows per locule, white, flattened or wedge-shaped, 4–5 mm, papery, wrinkled.

2n

= 44.

= 40.

Iris giganticaerulea

Iris orientalis

Phenology Flowering Mar–Apr. Flowering May–Jul.
Habitat Shallow water or very wet roadside ditches Persisting after cultivation or discarded along roadsides
Distribution
from FNA
AL; LA; MS
[WildflowerSearch map]
[BONAP county map]
from FNA
CA; CT; MO; expected elsewhere; Greece; Turkey [Introduced in North America]
[BONAP county map]
Source FNA vol. 26. FNA vol. 26, p. 394.
Parent taxa Iridaceae > Iris > subg. Limniris > sect. Limniris > ser. Hexagonae Iridaceae > Iris > subg. Limniris > sect. Limniris > ser. Spuriae
Sibling taxa
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
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. 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 Small: Addisonia 14: 5, plate 451. (1929) Miller: Gard. Dict. ed. 8, Iris no. 9. (1768)
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