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giant blue iris

coast iris, long-petal iris

Rhizomes

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

with short, creeping branches, stout, 2–2.5 cm diam., covered with bases of old leaves;

roots numerous, fleshy.

Stems

2–3-branched, solid, 10–15(–20+) dm.

simple or 1–2-branched, solid, 3–6 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 persistent, blade dark green, turning gray or yellow-brown when drying, veins not prominent, linear, 4–7 dm × 0.6–1 cm, usually longer than stem, glaucous or subglaucous, apex acute;

cauline 2–3, 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.

3–6-flowered;

spathes distant, inner sometimes 10 cm distal to outer, green, narrowly linear-lanceolate, 8–15 cm × 20–40 mm, herbaceous, margins and apex scarious.

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 pale blue-violet or nearly white, with lilac-purple veins;

floral tube funnelform, 0.5–1.3 cm;

sepals spreading, then drooping at apex, white, flecked and veined with violet, obovate, 8–10 × 3–5 cm, base attenuate into narrow claw with prominent yellow ridge, signal a yellowish basal patch;

petals semierect, oblong, 8–9 × 1.5–2 cm, base gradually attenuate, apex emarginate, bluntly rounded;

ovary trigonal with central ridge in each face, 2–5 cm;

style narrow basally, widening distally, 3.5–4 × 0.6–1 cm, crests overlapping basally, subquadrate, 1–1.5 cm, margins incised;

stigmas obscurely to prominently 2-lobed, margins crenate;

pedicels stout, 3–9 cm, unequal at anthesis, becoming ± equal at maturity.

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.

6-ribbed, oblong-ovoid, tapering to either end, almost round in cross section, 8–9 cm.

Seeds

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

dark brown, globular, wrinkled.

2n

= 44.

= 86, 88.

Iris giganticaerulea

Iris longipetala

Phenology Flowering Mar–Apr. Flowering Mar–Apr.
Habitat Shallow water or very wet roadside ditches Wet, heavy soil along coast
Distribution
from FNA
AL; LA; MS
[WildflowerSearch map]
[BONAP county map]
from FNA
CA
[WildflowerSearch map]
[BONAP county map]
Discussion

Iris longipetala hybridizes with I. missouriensis and is found from Mendocino County south to Monterey.

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

Source FNA vol. 26. FNA vol. 26, p. 389.
Parent taxa Iridaceae > Iris > subg. Limniris > sect. Limniris > ser. Hexagonae Iridaceae > Iris > subg. Limniris > sect. Limniris > ser. Longipetalae
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. 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) Herbert: in W. J. Hooker and G. A. W. Arnott, Bot. Beechey Voy., 395. (1840)
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