Iris ruthenica Ker Gawler var. uniflora (Pallas ex Link) Baker.

Rhizomes creeping, branched, brown. Roots fibrous. Leaves linear, 5--20 cm × 4--10 mm at anthesis, 30--40 × 1--1.5 cm in fruit, midvein absent, base surrounded by brown, persistent fibers. Flowering stems slender, 1-leaved; spathes 2, yellowish green, with slightly reddish margin, broadly lanceolate, 2--3.5 cm × 8--10 mm, membranous, 1-flowered, apex obtuse. Flowers violet, 4--4.5 cm in diam. Perianth tube ca. 1.5 cm; outer segments narrowly oblanceolate, ca. 3 cm × 8 mm; inner segments erect, narrowly lanceolate, ca. 3 cm × 3 mm. Stamens ca. 1.5 cm. Ovary ca. 5 mm. Capsule globose, 8--10 mm in diam., 6-ribbed. Fl. May--Jun, fr. Jul--Aug.

Iris uniflora is almost certainly merely a variety of I. ruthenica, as treated by Baker (Handb. Irid. 4. 1892). A form with narrow leaves (2--6 mm wide at anthesis, ca. 10 mm wide in fruit) was described as I. uniflora var. caricina Kitagawa (Bot. Mag. (Tokyo) 49: 232. 1935), but it is scarcely worth recognizing.

Forest margins, dry grasslands, hillsides, roadsides. Heilongjiang, Jilin, Liaoning, Nei Mongol [Korea, Mongolia, Russia].