Coreopsis grandiflora (Asteraceae)
The genus Coreopsis comprises 120 herbaceous or shrubby species belonging to the daisy family and they occur in tropical Africa, Hawaii and America. Two of the herbaceous species most often found in gardens are C. auriculata, which is about 60cm tall, and C. grandiflora growing to about 1 metre tall. Garden varieties have been selected from both species and these tend to have golden-yellow flowers with a crimson-maroon blotch at the base of each ray-floret, or buttercup yellow flowers overlaid with Indian yellow. While the plain yellow form is now regarded as a roadside weed and rarely offered for sale, this one with the crimson blotch is quite decorative and is one not often available.
2017 update: I am currently out of stock