Protea eximia bud in Kirstenbosch

Minimal blackening or browning of some Protea eximia involucral bract tips is seen here. The upper, inner and longer bracts are free from it at the time of the photo. The white, hairy fringes at bract-tips are not affected by the browning.

The heads are more concerned with looking pretty for catching pollinator eyes. For all we know the black rims contribute to that. It is still hard these days to find human experts on the aesthetic sense of insects. The lower, shorter and outer bracts are more work related than flaunting beauty or marketing pollen, keeping the flowerhead steadily in shape during the production process. Not all in this world are destined for limelight roles. 

The bract blades are quite loose from the head in picture, bulging in the centre and ready to part and spread. Control of flowerhead bits, keeping everything neatly in place, isn’t as big a priority in the comparatively unkempt-looking P. eximia heads. Many other Protea species bear neat, trim heads (Vlok and Schutte-Vlok, 2015; Coates Palgrave, 2002; Leistner, (Ed.), 2000; Rebelo, 1995; Rourke, 1980; iNaturalist).