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Iris douglasiana

Douglas' iris, mountain iris

beach-head iris

Rhizomes

freely branching, forming large colonies, slender, 0.8–0.9 cm diam., covered with remains of old leaves;

roots fibrous.

many-branched, producing dense clumps, 3–6 × 1.5–2 cm, covered with remnants of old leaves.

Stems

1–4-branched, solid, 1.5–7 dm.

1–2-branched, 1.5–9 dm, exceeding leaves;

branches 1.25–1.5 dm proximal to terminal, but bearing flowers on nearly the same level.

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 with blade green with purple tinge basally, prominently ribbed, ensiform, 0.2–0.45 dm × 1–2 cm, ± glaucous distally;

cauline subtending each lateral branch, blade reduced, 0.5–1.5 dm.

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, lateral units usually 2-flowered;

spathes green flushed with purple, foliaceous, ovate-lanceolate, 2.5–4.5 cm × 5–7 mm, unequal, inner longer than outer, sometimes scarious.

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 dark blue-violet to red-purple with darker veins;

floral tube ca. 0.7 cm;

sepals 4–6 × 3–5 cm, glabrous, base abruptly attenuate to broad claw with undulate margins;

petals much reduced, 1–2 × 0.3–0.4 cm, widest basally, mostly hidden by bases of outer sepals, apex acuminate, with 3–8 mm bristle;

ovary conspicuously 3-angled, inflated at anthesis, 1.3 cm;

style 2.5 cm, crests overlapping, subquadrate, 0.7 cm, margins incised;

stigmas semicircular, margins entire;

pedicel 2.5–4.5 cm, ± equaling spathes.

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.

roundly trigonal, 2.5 × 1.3–1.5 cm.

Seeds

dark brown, pyriform, wrinkled.

in 2 rows per locule, light brown, with prominent raphe, D-shaped, 2–3 mm, very smooth.

2n

= 40.

= 34, 36, 38.

Iris douglasiana

Iris setosa

Phenology Flowering Apr–Jun. Flowering Jul–Aug.
Habitat Open woods, sunny slopes and fields Boggy meadows, shores, and dunes
Distribution
from FNA
CA; OR
[WildflowerSearch map]
[BONAP county map]
from FNA
AK; BC; YT; e coastal Asia to Japan
[WildflowerSearch map]
[BONAP county map]
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.)

Iris setosa was originally described from Siberia; whether our populations are an extension from or were formerly continuous with the Asian ones is not known. Two varieties from Japan, var. hondoensis Honda and var. nasuensis Hara, with 2n = 54 may be triploids.

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

Source FNA vol. 26, p. 384. Treatment author: Norlan C. Henderson. FNA vol. 26, p. 380. Treatment author: Norlan C. Henderson.
Parent taxa Iridaceae > Iris > subg. Limniris > sect. Limniris > ser. Californicae Iridaceae > Iris > subg. Limniris > sect. Limniris > ser. Tripetalae
Sibling taxa
I. bracteata, I. brevicaulis, I. chrysophylla, I. cristata, 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
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. longipetala, I. macrosiphon, I. missouriensis, I. munzii, I. orientalis, I. pallida, I. prismatica, I. pseudacorus, I. pumila, I. purdyi, I. savannarum, I. sibirica, I. tenax, I. tenuis, I. tenuissima, I. tridentata, I. verna, I. versicolor, I. virginica
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. arctica
Name authority Herbert G. A. W. Arnott: in W. J. Hooker and G. A. W. Arnott, Bot. Beechey Voy., 395. (1840) Pallas ex Link: Jahrb. Gewächsk. 1(3): 71. (1820)
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