The golden yellow flowerhead of Heterolepis aliena is large, up to 6 cm in diameter. It grows on a sandpapery, leafless stalk that becomes about 5 cm long. Two or three rows of narrow, oblong, green involucral bracts hold the base of the flowerhead below the corolla. The inner row of bracts has membranous margins. There are no scales on the receptacle.
The ray florets are narrowly elliptic with rounded tips and channelled surfaces, growing in roughly two rows around the disc. The ray florets are female. They have thread-like, narrow lobes inside the disc, each opposing its ray. Disc florets are five-lobed and fertile. The plant may flower profusely in season, from spring to midsummer (Manning, 2007).