Erica coccinea resembles E. plukenetii in having far exserted, usually pendulous stamens. Both species have several flower colours, some that are similar. A distinguishing characteristic is the large bracts at the back of the flower of E. coccinea that spread over the sepals. In the photo the corolla, the sepals and the bracts form three yellow layers of different length on the flower tube. In E. plukenetii the bracts are small, insignificant and further back on the stalk, the peduncle.
E. coccinea leaves are also tufted and shorter as can be seen here, while longer, whorled leaves look feathery on E. plukenetii stems (Baker, et al, 1967).