Iris giganticaerulea |
Iris douglasiana |
|
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giant blue iris |
Douglas' iris, mountain iris |
|
Rhizomes | green, extensively branched, forming large clumps, 2–4 cm diam., with pale leaf scars. |
freely branching, forming large colonies, slender, 0.8–0.9 cm diam., covered with remains of old leaves; roots fibrous. |
Stems | 2–3-branched, solid, 10–15(–20+) dm. |
1–4-branched, solid, 1.5–7 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 yellow-green, occasionally darker green, sometimes flushed pink or red basally, prominently ribbed, linear, 4.5–10 dm × 2 cm, apex acute; cauline 1–3, 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. |
(2–)3-flowered, branch units 2–3-flowered; spathes opposite or separated, divergent, green, sometimes flushed purple basally, lanceolate-acuminate, 6–12 cm × 7–12 mm. |
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 red-purple, lavender, gray-blue, cream, or white, with gold signal and blue or purple veins; floral tube 1.5–2.8 cm, usually widening to bowl shape at base of flower; sepals oblanceolate to obovate, 5–9 × 1.4–3 cm, base gradually attenuate, apex obtusely rounded; petals oblanceolate, 4.5–7 × 0.9–1.8 cm, base attenuate to narrow claw; ovary elliptic-oval, sharply triangular in cross section, 3–4 cm; style 1.7–3.5 cm; crests overlapping, subquadrate, 1–2 cm, margins coarsely toothed; stigmas triangular; pedicel 2–5 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. |
sharply triangular in cross section with ridge at each angle, tapering at both ends, remnant of floral tube forming tip at apex, 2.5–5 cm. |
Seeds | in 2 rows per locule, brown, D-shaped, 8–10 mm wide, very corky. |
dark brown, pyriform, wrinkled. |
2n | = 44. |
= 40. |
Iris giganticaerulea |
Iris douglasiana |
|
Phenology | Flowering Mar–Apr. | Flowering Apr–Jun. |
Habitat | Shallow water or very wet roadside ditches | Open woods, sunny slopes and fields |
Distribution |
AL; LA; MS
|
CA; OR
|
Discussion | R. C. Foster (1937) named several varieties of Iris douglasiana, about which L. W. Lenz (1954) said, “This is a widespread and extremely variable species whose total variability is being increased due to introgressive hybridization between it and other species with which it has come into contact. Well marked and distinct geographic races cannot be detected; however, pronounced variations are to be found within a single population. For these reasons no attempt is made here to segregate taxa within such a polymorphic species.” Iris douglasiana hybridizes with I. bracteata, I. chrysophylla, I. fernaldii, I. hartwegii, I. innominata, I. macrosiphon, I. munzii, I. purdyi, I. tenax, and I. tenuissima. The natural hybrid between I. douglasiana and I. innominata has been designated as Iris ×thompsonii R. C. Foster and the garden hybrid as Iris ×aureonympha E. H. English. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
|
Source | FNA vol. 26. | FNA vol. 26, p. 384. |
Parent taxa | Iridaceae > Iris > subg. Limniris > sect. Limniris > ser. Hexagonae | Iridaceae > Iris > subg. Limniris > sect. Limniris > ser. Californicae |
Sibling taxa | ||
Synonyms | I. elephantina, I. hexagona var. giganticaerulea, I. miraculosa | I. beecheyana, I. douglasiana var. alpha, I. douglasiana var. altissima, I. douglasiana var. beecheyana, I. douglasiana var. bracteata, I. douglasiana var. major, I. douglasiana var. mendocinensis, I. douglasiana var. nuda, I. douglasiana var. oregonensis, I. watsoniana |
Name authority | Small: Addisonia 14: 5, plate 451. (1929) | Herbert G. A. W. Arnott: in W. J. Hooker and G. A. W. Arnott, Bot. Beechey Voy., 395. (1840) |
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