The stipules have a well developed tubular sheath that splits into triangular segments, has several linear appendages, and become corky; the inflorescences are rather short and cymose (described as panicles in the protologue but clearly illustrated there as determinate; the orollas are funnelform, 110-11 mm long, and have lobes with rounded abaxial horns. Rudgea billietiae is similar to Rudgea hostmanniana, which differs in it shorter broader stipule sheath and lobes.