Rhizomes erect, thick, producing slender stolons. Leaves grayish green on 1 surface, bright green on other, sword-shaped, 30--40 × 2--2.5 cm, veins 3--5. Flowering stems 4- or 5-branched, 30--40 cm; spathes 4--6, green, 3--5-flowered, margin membranous. Flowers whitish, 7--8 cm in diam. Perianth tube ca. 1 cm; outer segments obovate, 4--5 × ca. 2.5 cm, limb reflexed, with blue lines and yellow-brown spots around prominent crest, margin denticulate, undulate; inner segments speading obliquely, pale blue, oblanceolate to oblong, 2.5--3 × ca. 1.5 cm, adaxially with dense, glandular trichomes, margin slightly denticulate. Anthers oblong to linear, 8--9 mm; filaments white, ca. 1.5 cm. Ovary ca. 1 cm. Style branches pale blue, ca. 2 cm × 6--7 mm; terminal lobes fimbriate. Capsule oblong to ovoid-cylindric, apex with persistent perianth tube. 2 n = 28*.

Two of us (Noltie and Mathew) consider this species to be doubtfully distinct from Iris japonica.

* Forest margins, hillsides, roadsides; 500--1000 m. NE Taiwan.