Coburgia splendens is now considerd to be synonymous with Clinanthus incarnatus (Kunth) Meerow which see. Herbert considered it to be a separate species as described below. Macarthur also no doubt considered it to be a good species and it is treated separately here for ease of identification. 

‘Perianthemum coccineum apice virescens, laciniis longioribus acutioribus; folia carent.  It is impossible to decide, without more perfect knowledge of these plants, whether this splendid flower should be considered as var. splendens of incarnata, or as distinct.  It differs both in colour and the form of the segments of the limb.  The leaves are wanting.’  [Herbert p.400/1837].  Herbert plate 47/1837.