A. The Genus Iris - Sepals and petals dissimilar, the sepals being much larger, often pencilled with dark brown to purplish markings. The smaller petals alternate with the sepals. The petal-like style branches originate from the upper base of the sepals and curve over the sepals to closely cover them. Each style branch ends in two lobes that are reflexed upwards (See photo above.).

1. Rocky Mountain Iris, Rocky Mt. Iris, Western Blue Flag Iris missouriensis - Flowers bluish, lavender or whitish with yellowish palate. Plants with thick rhizomes with flower scapes 40-80 cm high. Flower scapes leafless or with a single flower. Native wildflowers of vernally moist meadows and streambanks, generally east of the Cascade crest.

2. Pale Yellow Iris, Yellow Flag, Yellow Water Iris Iris pseudacorus - Flowers pale to bright yellow. Plants often taller than 1 meter. Plants of lake margins and most ditches. Introduced from Europe.

3. Oregon Flag, Oregon Iris, Tough-leaved Iris Iris tenax var. tenax (Synonyms: Iris tenax var. gormanii, Iris tenax ssp. klamathensis, Iris tenax var. marshallii, Iris tenax ssp. tenax) - Flowers bluish, lavender or whitish with yellowish palate. Plants with slender rhizomes with flower scapes generally less than 40 cm high. Native wildflowers of vernally moist meadows west of the Cascade crest.

B. Grasss Widows: The Genus Olsynium - Petals and sepals reddish-purple, generally the same size and shape. Style branches small, slender and not petal-like. Filaments fused only on the lower 1/3-1/2 of their length.

1. Satin Flower, Grass Widow Olsynium douglasii (Synonym: Sisyrinchium douglasii var. douglasii) - Filament tube only slightly enlarge at its base. Flowers deep reddish-purple.

2. Grass Widow Olsynium inflatum (Synonym: Sisyrinchium douglasii var. inflatum) - Filament tube inflated or swollen at a point just above the base. Flowers generally light purple.

C. Blue-eyed Grasses: The Genus Sisyrinchium - Petals and sepals more bluish than red, generally the same size and shape. Style branches small, slender and not petal-like. Filaments fused from their base to near the tip.

1. Blue-eyed Grass Sisyrinchium idahoense (previously S. angustifolium) -