Thereianthus bracteolatus flowers have brown, dry bracts at the base of their straight corolla tubes. The oblong to obovate and more blue than purple tepals in picture spread, angled out with pointed tips. Red-purple blotches are present on the blades.

The three anthers are white and erect in the flower centre, their filaments bluish. The style has three branches, each split for half its length.

The plant is sometimes known as common summerpipes (Manning, 2007; iNaturalist).