The flower on this plant is similar to that of A. tricolor, which usually has larger bowl-shaped calyces and more white in the flower; the calyx can be a variety of colors. A. cordifolius has been described as more shrubby, tricolor as more trailing; they may be variants of the same species.
The calyces on plants in cultivation as A. cordifolius vary considerably; most often they have smallish bowl-shaped calyces, but sometimes the calyx is more firmly grasping the base of the corolla. Early illustrations of the species are more often of the latter type, as can be seen here.
Additional photos may be seen in a slideshow by clicking one of the links below:
