Iris douglasiana |
Iris virginica |
|
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Douglas' iris, mountain iris |
iris de virginie, southern blue flag, Virginia iris |
|
Rhizomes | freely branching, forming large colonies, slender, 0.8–0.9 cm diam., covered with remains of old leaves; roots fibrous. |
many-branched, forming dense clumps, 2–4 cm diam., usually covered with remnants of old leaves; roots fleshy. |
Stems | 1–4-branched, solid, 1.5–7 dm. |
rather weak, often falling over after flowering, solid, usually 1-branched, 5–10 dm. |
Leaves | 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. |
basal erect or often flexible, blade gray-green to bright green, buff to purplish basally, with several prominent ribs in mature leaves, linear-ensiform, 6–8 dm × 2.5–3 cm, apex acute. |
Inflorescence units | (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. |
2–3-flowered, branch units 1–2-flowered; spathes compact, often with brown striations, ridged, unequal, outer 3–8 cm, inner 8–14 cm, firm, herbaceous. |
Flowers | 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. |
perianth lavender to violet, rarely white; floral tube constricted above ovary, 1–2 cm; sepals spreading and arched, pale blue to purple with darker blue or purple lines, obovate to oval, 4–8.4 × 1.6–4 cm, base abruptly attenuate, claw green in median, bordered by yellow ground with blue or purple lines, yellow extending onto base of limb as finely pubescent signal patch; petals oblong-lanceolate to oblong-spatulate, 3–7 × 1–3 cm, claw greenish yellow with blue or purplish lines, apex often emarginate; ovary trigonal, 1.3–3.8 cm; style inwardly auriculate at convergences, 3–4.5 cm, crests reflexed, 0.7–2 cm; stigmas unlobed, with prominent triangular tongues, margins entire; pedicel 2.5–8 cm. |
Capsules | 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. |
ovoid, ellipsoid, or long-cylindric, trigonal or polygonal in cross section, 3–6 × 1–2 cm. |
Seeds | dark brown, pyriform, wrinkled. |
in 2 rows per locule, pale brown, usually D-shaped, 5–8 mm, pitted, corky. |
2n | = 40. |
= 70, 72. |
Iris douglasiana |
Iris virginica |
|
Phenology | Flowering Apr–Jun. | Flowering May–Jun. |
Habitat | Open woods, sunny slopes and fields | Wetlands, margins of lakes and streams |
Distribution |
CA; OR
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AL; AR; DC; FL; GA; IA; IL; IN; KS; KY; LA; MD; MI; MN; MO; MS; NC; NE; NY; OH; OK; PA; SC; TN; TX; VA; WI; WV; ON; QC
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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.) |
Plants of Iris virginica from the southeastern and south-central states having stems 2–3-branched and seldom falling to the ground after flowering, and with capsules long-cylindric have been recognized as var. shrevei. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 26, p. 384. | FNA vol. 26, p. 390. |
Parent taxa | ||
Sibling taxa | ||
Synonyms | 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 | I. caroliniana, I. georgiana, I. shrevei, I. virginica var. shrevei |
Name authority | Herbert G. A. W. Arnott: in W. J. Hooker and G. A. W. Arnott, Bot. Beechey Voy., 395. (1840) | Linnaeus: Sp. Pl. 1: 39. (1753) |
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