Orbea lutea subsp. lutea flowers grow in inflorescences of 3 to 26, mostly from middle or lower parts of young stems. The stout and hairless pedicels are up to 2,5 cm long. The canary-yellow flowers end in five long, narrow and pointed corolla lobes. The spreading corollas are hairless on the outside, ridged or wrinkled inside. Corollas are sometimes over 6 cm wide. Many of the flowers open at the same time.
The outer corona is cup-shaped with recurved margin, ending in five lobes. The inner corona lobes are thread-like, erect to curving in. They are connected at the back to the dips or sinuses between the outer corona lobes where solitary teeth are present.
A gathering of tiny insects, including some flies relishing the floral odour interact with the flowers here, in a long-standing, mutually beneficial event involving different species. The possibility may be considered that synchronous blooming intensifies the pungent floral odour resembling the smell of decaying organic matter and may increase its reach. This should add to visitor numbers; a remarkably useful adaptation if it's true (Smith, et al, 2017; White and Sloane, 1937; iNaturalist; https://pza.sanbi.org).