Ecology, Spread & Impact of Lippia

Summary

Lippia (Phyla canescens: Verbenaceae) is a serious weed of wetlands, riparian zones and floodplains, particularly in eastern Australia where many Ramsar wetlands are threatened by hydrological changes precipitated by soil accreting lippia mats Three distinct P. canescens genotypes have been identified, two from the native range, and one that has so far only been found in France (presumably from an as yet unidentified American population). The two genotypes in South America are geographically isolated (SE coastal and NW inland Argentina). French and Australian populations are represented by numerous genotypes, suggesting multiple introductions (or considerable crossing/domestication prior to introduction) Glasshouse experiments revealed that P. canescens does not set seed without pollinators (is not autonomous). Experiments are underway to study more aspects of reproductive biology of the species. On the other hand P. nodiflora is autonomous and produces seeds without the need for pollinator.