Roof Iris is beautiful blue-flowered Iris native to China, Korea, Japan and
possibly Myanmar. Roof iris is so named because it used to be grown in
thatched roofs in parts of Japan. It is seen naturalized in hill stations
like Mussoorie. The plant has creeping, thick rhizomes and slender roots.
Leaves occur mainly in fans arising from the base, yellowish green, broadly
sword-shaped, curved, 15-50 cm long and 1.5-3.5 cm wide, with base
surrounded by fibers. Flowering stems are 1- or 2-branched, 20-40 cm long,
1- or 2-leaved. Flowers are bluish violet, about 10 cm in diameter, with
stalk to 1 cm. Flower tube is slender, to 3 cm. Outer petals are mottled
darker around conspicuous, white, irregularly toothed crest. These petals
are broadly ovate, 5-7 × 4 cm. Inner petals spread horizontally in the
fully open flower. These are elliptic, 4.5-5 × 3 cm. Stamens about 2.5 cm,
anthers bright yellow. Style branches pale bluish violet, about 3.5 cm.
Capsule ellipsoid or obovoid, 4.5-6 × 2-2.5 cm. Flowering: April-May.