E-Flora BC: Electronic Atlas of the Flora of British Columbia

Iris missouriensis Nutt.
western blue iris (Rocky Mountain iris)
Iridaceae (Iris family)

Introduction to Vascular Plants

© Thayne Tuason  Email the photographer   (Photo ID #76371)

E-Flora BC Static Map
Distribution of Iris missouriensis
Click here to view our interactive map and legend
Details about map content are available here
Click on the map dots to view record details.

Species Information

Click on the image below to view an expanded illustration for this species.

Perennial herb from a thick rhizome; flowering stems usually simple, sometimes branched, 20-50 cm tall.
Mostly basal, linear-lanceolate, 20-50 cm long, 5-10 mm wide, entire, the tips long-pointed.
Inflorescence of 1 or 2, sometimes 3 or 4, showy flowers on stout, 4- to 6-cm long stalks; flowers light to deep blue, purple-lined, the tubes flared above, less than 6 mm long, the bracts green or reddish and not papery at flowering; petals erect, 3-6 cm long, 1.5-2 cm wide; sepals oblanceolate, 5-6 cm long, about 1 cm wide, bent back; style branches 2-2.5 cm long, the crests less than 1/2 as long; stigmas 2-lobed.
Capsules, cylindrical, 3-5 cm long; seeds numerous.

Source: The Illustrated Flora of British Columbia

USDA Species Characteristics

Flower Colour:
Blooming Period:
Fruit/Seed characteristics:
Colour: Black
Present from Summer to Spring
Source:  The USDA

Habitat / Range

Moist lake margins and marshy meadows in the lowland and montane zones; rare in W BC, known from scattered localities, where probably introduced; E to SE AB and S to MN, NE, NM, AZ, CA and N MX.

Source: The Illustrated Flora of British Columbia


The climate type for this species, as reported in the: "British Columbia plant species codes and selected attributes. Version 6 Database" (Meidinger et al. 2008), is not evaluated, unknown or variable.

Synonyms and Alternate Names

Iris longipetala Herbert
Iris missouriensis var. arizonica (Dykes) R.C. Foster
Iris missouriensis var. pelogonus (Goodding) R.C. Foster
Iris pariensis S.L. Welsh
Iris tolmieana Herbert

Taxonomic and Nomenclatural Links

Additional Photo Sources

General References