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giant blue iris

golden leaf iris, slender-tubed iris, yellow-flower iris, yellow-leaf iris

Rhizomes

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

compact, dark brown, slender, 0.5–0.6 cm diam., covered with old leaf bases;

roots few, fibrous.

Stems

2–3-branched, solid, 10–15(–20+) dm.

simple, solid, slender, 0.25–2 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 with blade light green, pink or red-tinged basally, finely ribbed, linear-acute, 2.5–5 dm × 0.3–0.5 cm, somewhat glaucous, margins not thickened;

cauline 1–3, imbricated, blade bractlike, inflated.

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.

usually 2–flowered;

spathes sometimes flushed pink or purple apically, lanceolate to linear-lanceolate, 5–10 cm × 3–7 mm, unequal, outer much shorter and narrower than inner, herbaceous, margins often scarious, apex acute.

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 cream or very pale yellow, with deeper yellow or lavender veins;

floral tube linear, slender, 4.5–12 cm;

sepals with bluish tinge and veins, oblanceolate, 4.6–7 × 1–2 cm, base gradually attenuate;

petals lanceolate, 3–5.5 × 0.6–1.2 cm, base gradually attenuate, apex emarginate;

ovary 1–1.8 cm, base abruptly attenuate into pedicel (when present), apex gradually acuminate into floral tube;

style 2–3 cm, crests 1.5–2 cm, sometimes exceeding arms, apex narrowly pointed;

stigmas tongue-shaped, margins entire;

pedicel absent or 0.5–1 cm at anthesis.

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.

sometimes on elongated pedicel, oblong, round in cross section, sharply beaked, 2–3 cm.

Seeds

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

buff, slightly compressed.

2n

= 44.

= 40.

Iris giganticaerulea

Iris chrysophylla

Phenology Flowering Mar–Apr. Flowering Apr–Jun.
Habitat Shallow water or very wet roadside ditches Open, coniferous forests
Distribution
from FNA
AL; LA; MS
[WildflowerSearch map]
[BONAP county map]
from FNA
CA; OR
[WildflowerSearch map]
[BONAP county map]
Discussion

Iris chrysophylla hybridizes with I. bracteata, I. douglasiana, I. innominata, I. macrosiphon, I. purdyi, I. tenax, and I. tenuissima.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Source FNA vol. 26. FNA vol. 26, p. 386.
Parent taxa Iridaceae > Iris > subg. Limniris > sect. Limniris > ser. Hexagonae Iridaceae > Iris > subg. Limniris > sect. Limniris > ser. Californicae
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. 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. 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) Howell: Fl. N. W. Amer., 633. (1902)
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