Plants small, 25--50 cm tall, deciduous in winter. Roots slightly fleshy, with oblong, swollen, tuberous part near tip. Leaves linear, narrow, nearly as long as scape, 40--45 × 1.5--2 cm. Scape ascending. Inflorescence short, a 2--4-flowered helicoidal cyme; basal pedicel usually concaulescent; bracts oblong-ovate, apex subacute. Flowers rather small, slightly fragrant, opening in very early morning and closing in very early morning of following day, reddish brown apically in bud. Perianth orange-yellow; tube rather short, ca. 1 cm; segments narrow, 5--7 cm, outer ones 0.7--1 cm wide, inner ones slightly wider than outer, 1--1.5 cm wide. Anthers black. Capsule subovoid. Fl. May--Jun. 2 n = 22.

This species was reported from S Jilin by Kitagawa (Lin. Fl. Manshur. 136. 1939) and Noda (Fl. N-E. Prov. (Manchuria) China 280. 1971). However, the present authors have not seen any specimens in Chinese herbaria. Hemerocallis dumortieri is closely related to H. esculenta and H. middendorffii, both of which have been treated by some authors as varieties of H. dumortieri.

?S Jilin [Japan, Korea, Russia (E Siberia)].