Fig. 2. Reflectance spectra of flowers of the nine asclepiads from Wahroonga. In all cases the dark line is the spectrum of the corona and the light line is the spectrum of the corolla. For Pachycarpus natalensis, the lower, light coloured line is the spectrum for the large purple patches (see Fig. 1A and B). For Sisyranthus trichostomus, the corona is not visible without dissecting the flower.