Leaves 15–40 cm × 3–12 mm. Scape 10–35 cm, smooth or slightly scabrous near base. Flowers: perianth yellow or white, often tinged or fading blue, 18–26 mm, tube slenderly funnelform, moderately attenuate at base, 6–10 mm, lobes widely spreading, with conspicuous dark purple midvein, 12–16 mm, ca. twice as long as tube; stamens attached at 1 level, nearly equal; filaments narrowly subulate, 3–4 mm, apical appendages absent; anthers blue or sometimes white, 1.5–2 mm; ovary 1/2 as long as stipe; pedicel 1.5–4 cm. 2n = 32.