Phenotypic plasticity among Echium plantagineum populations in different habitats of Western Cape, South Africa

This paper addresses phenotypic variation among Paterson's Curse (Echium plantagineum L.) populations in four different habitat types (tar road verges, dirt road verges, abandoned fields and natural areas) in the Western Cape region of South Africa. The species showed significant differences in plant height, seed size and seed weight with varying habitats. The reproductive index (Ri), comprising a ratio of total number of seeds to the height of the plant, demonstrated the plastic behavior of E. plantagineum in the various habitats. Results indicate that plastic responses to different habitat types contribute to E. plantagineum invasiveness, allowing range expansion and establishment through production of lighter and heavier seeds, respectively.