Leptospermum scoparium

Continued evolution

Leptospermum scoparium is in the process of evolutionary differentiation as a result of its isolation from fellow members of the Leptospermum genus. New studies demonstrate a loss of lignotubers among populations of Leptospermum scoparium located in relatively fire-free zones of New Zealand's South Island, while Australian and Tasmanian populations retain their lignotubers along with stronger manifestations of serotiny. Australian populations of Leptospermum scoparium are shown to be chemically distinct from their New Zealand counterparts, with significantly higher levels of cinteole and monoterpines. Chemotypical variations also exist between different populations within New Zealand, leading some to suggest that L. scoparium be divided into three subspecies: those with high pinenes, high triketones, and high sesquiterpenes. Recently, however, new research suggests that plant-to-plant variation far outstrips the variation seen between geographically isolated manuka sites, at least with regard to nectar chemistry.