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giant blue iris

beach-head iris, iris de Hooker

Rhizomes

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

many-branched, forming dense, cespitose clumps with many crowded fans with persistent old leaf bases, 3–5 × 1.3–1.5 cm.

Stems

2–3-branched, solid, 10–15(–20+) dm.

several to many from a single clump of fans, simple, 0.5–6 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 erect or strongly ascending, blade 1–5.2 dm × 0.5–1.4 cm;

cauline 2–4, proximal 2–3 similar to basal leaves, distalmost leaf occasionally borne nearly midway on stem, clasping, blade bracteiform, lanceolate, 0.5–1.5 dm.

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.

1–2-flowered;

spathes herbaceous, lanceolate to oblong-ovate, 2.5–6 cm, firm, outer spathe apex acute, inner similar or scarious at apex.

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 deep to pale blue or blue-violet;

floral tube 0.5–0.75 cm;

sepals broadly rounded, 2.5–4 cm wide, base strongly attenuate to claw, signal diffuse white basal patch;

petals much reduced to insignificant, involute or tubular rudiments, 1–2 cm, apex with short bristle, mostly hidden by sepal bases;

ovary green or flushed purple, acutely trigonal;

style white with purple keel, 2–5 cm, crests overlapping, 2-lobed, subquadrate, margins coarsely serrate;

stigmas rounded-triangular, margins entire;

pedicel 2.5–4 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.

thin walled, trigonal, with rounded angles and grooved sides, 2–4 cm, apex blunt.

Seeds

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

in 2 rows per locule, dark brown with prominent white raphe, compressed-pyriform, 4–6 mm, lustrous.

2n

= 44.

= 38.

Iris giganticaerulea

Iris hookeri

Phenology Flowering Mar–Apr. Flowering Jun–Jul.
Habitat Shallow water or very wet roadside ditches Grassy headlands, upper borders of beaches, dunes, and other coast formations, within reach of ocean spray
Distribution
from FNA
AL; LA; MS
[WildflowerSearch map]
[BONAP county map]
from FNA
ME; NB; NL; NS; PE; QC
[BONAP county map]
Discussion

Some authors still treat this taxon as Iris setosa var. canadensis, but others believe that it merits recognition as a separate species. I have seen I. hookeri flowering in its native habitat in both Nova Scotia and Prince Edward Island, and have examined dozens of herbarium specimens of both it and I. setosa, from which it is clearly distinct.

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

Source FNA vol. 26. FNA vol. 26, p. 381.
Parent taxa Iridaceae > Iris > subg. Limniris > sect. Limniris > ser. Hexagonae Iridaceae > Iris > subg. Limniris > sect. Limniris > ser. Tripetalae
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. 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 I. canadensis, I. setosa var. canadensis, I. setosa subsp. pygmaea
Name authority Small: Addisonia 14: 5, plate 451. (1929) Penny ex G. Don: in J. C. Loudon, Hort. Brit. ed. 2, 591. (1832)
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