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Oregon flag, Oregon iris, tough-leaf iris

long-tube iris, slender iris

Rhizomes

many-branched, not creeping, forming dense clumps, slender, 0.3–0.8 cm diam.;

roots fibrous.

freely branching, producing dense clumps, slender, 0.5–0.7 cm diam., covered with bases of old leaves;

roots fibrous.

Stems

simple, somewhat angular, solid, 1.5–2.7 dm.

simple, solid, 2–3 dm.

Leaves

basal somewhat lax, overtopping stem, blade light green, paling to pink or straw color basally, finely ribbed, linear-acute to linear, ensiform, 4.5 dm × 0.5 cm, margins not thickened;

cauline 1–3, sheathing for 1/2 length then spreading, foliaceous, blade linear-lanceolate, not inflated, narrow, reduced, to 15 cm.

basal with blade sometimes pink to red basally, finely ribbed, linear, 3–3.5 dm × 0.5 cm, subglaucous, margins not thickened, apex acute;

cauline 1–3, imbricated, mostly free, bractlike, blade linear-lanceolate, inflated.

Inflorescence units

1–2-flowered;

spathes distant basally by 3 cm in some cases, keeled, linear-lanceolate to lanceolate-acuminate, 5–7 cm × 2–4 mm, unequal, outer longer than inner, herbaceous, margins scarious.

(1–)2-flowered;

spathes often flushed with pink or red, lanceolate, 4–8 cm × 5–10 mm, subequal or unequal and inner somewhat longer than outer, rigid, apex acuminate.

Flowers

perianth color variable, purple, pink, lavender, cream, yellow, or rarely white;

floral tube funnelform, 0.6–2 cm;

sepals veined with color of limb, obovate, 5.8–6 × 1.6–2 cm, base gradually attenuate into white claw with slight yellow ridge, apex emarginate to bluntly rounded;

petals same color as sepals, not prominently veined, lanceolate to oblanceolate, 5 × 1 cm;

ovary 1–2 cm, slightly wider distally, base very gradually attenuate;

style 2.2–3.2 cm, crests subquadrate, 8–12 mm, margins crenate or incised;

stigmas triangular, margins entire;

pedicel 1–5 cm, longer in second flower (when present) than in first.

perianth pale cream with distinct veins of lavender, reddish brown, or brown, margins often distinctly crisped;

floral tube funnelform, 3–5.8 cm, slender, then expanding abruptly to base of flower;

sepals spreading outward from base and remaining in horizontal position for entire length, narrowly lanceolate to oblanceolate, 4–6.5 × 1.1–1.8 cm, base attenuate into long claw;

petals somewhat spreading, not strictly erect, 4.5–6.5 × 0.6–1.4 cm, base gradually attenuate;

ovary 1–2 cm, gradually tapering to each end;

style 2–3 cm, crests linear, undulate near tip, 1–2.5 cm;

stigmas triangular;

pedicel 0.8–1.8 cm at anthesis.

Capsules

oblong, triangular in cross section, prominently ribbed, beaked, 3–5 cm.

oblong, round in cross section, 3–4 cm, base abruptly attenuate into pedicel, apex gradually acuminate into distinct beak apically.

Seeds

brown, D-shaped to irregular, wrinkled.

grayish brown, pyriform to oval, 3 mm, wrinkled.

2n

= 40.

Iris tenax

Iris tenuissima

Phenology Flowering Jun–Aug. Flowering Jun–Jul.
Habitat Dry soils in fields and open woods Dry, sunny woods
Distribution
from FNA
CA; OR; WA
[WildflowerSearch map]
[BONAP county map]
from FNA
CA
[WildflowerSearch map]
[BONAP county map]
Discussion

Plants described as subsp. klamathensis differ from others of the species in having floral tubes 11–20 mm instead of 6–10 mm, style crests somewhat longer and narrower, and flower color and markings more like those of Iris bracteata or I. innominata. The latter species has an even longer floral tube, 15–30 mm, which could be evidence of introgression. Hybrids are known to occur in the area common to both species, in Douglas County, Oregon.

Iris tenax hybridizes with I. bracteata, I. chrysophylla, I. douglasiana, I. hartwegii, I. innominata, I. macrosiphon, I. purdyi, and I. tenuissima.

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

Iris tenuissima hybridizes with I. chrysophylla, I. douglasiana, I. hartwegii, I. macrosiphon, I. purdyi, and I. tenax.

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

Source FNA vol. 26, p. 383. FNA vol. 26, p. 386.
Parent taxa Iridaceae > Iris > subg. Limniris > sect. Limniris > ser. Californicae Iridaceae > Iris > subg. Limniris > sect. Limniris > ser. Californicae
Sibling taxa
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. setosa, I. sibirica, 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. setosa, I. sibirica, I. tenax, I. tenuis, I. tridentata, I. verna, I. versicolor, I. virginica
Synonyms I. gormanii, I. tenax var. gormanii, I. tenax subsp. klamathensis I. citrina, I. humboldtiana, I. tenuissima subsp. purdyiformis, I. tenuissima var. purdyiformis
Name authority Douglas ex Lindley: Edwards’s Bot. Reg. 15: plate 1218. (1829) Dykes: Gard. Chron., ser. 3, 51: 18. (1912)
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