Cormous geophyte up to 50cm. Leaves 3, 3-9mm wide, linear, midrib thickened. Uppermost cataphyll usually mottled purple and white. Flower spike is erect and unbranched with usually 4-6 flowers; flowers are variable, blue to grey to violet, shades of yellow, occasionally pink, lower tepals have a yellow band across that may be outlined above and/or below with reddish to purple streaks; fragrant. Anthers cream, pollen cream. Bracts green or greyish or purplish green with transparent margins.

Latin: carinatus = with a keel; referring to the raised midvein on the leaf blade.