Presentation on theme: "Well, it looks a bit like… Alligator weed Friends and Foes? Gary Houliston Landcare Research, Lincoln, New Zealand."— Presentation transcript:
Well, it looks a bit like… Alligator weed Friends and Foes? Gary Houliston Landcare Research, Lincoln, New Zealand
Alternanthera in New Zealand Currently three species described –Alternanthera philoxeriodes (Alligator Weed) –Alternanthera denticulata (Australian import) –Alternanthera nahui (Endemic) A. nahui was formerly described as A. sessilis Is A. nahui endemic, native, or a recent import?
A. nahui Small leaves, ovary compressed, short stamen Study also relied strongly on ITS sequence data What about the other small-leaved Alternanthera in Australia?
Alternanthera in Australia Ca. 8 species in Australia Some known weeds in other parts of the world (A. nodiflora) Ca. 3 undescribed entities / known taxonomic problems
Genetic / Genomic study of Alternanthera 15 samples, 6 different species from Australia Several different A. nahui samples from New Zealand ITS sequencing / genome sizing via flow cytometry
Genome Size = 2.59 ± Genome Size = 2.52 ± 0.025
Is A. nahui endemic? Highly unlikely Similar to several Australian samples –A. sessilis –A. denticulata small green leaves –A. sp A –A. nodiflora (small rather than large inflorescences)
A. nodiflora in Africa…. Flora Zambesiaca: Inflorescences sessile…7-10mm. in diam.,… ovary strongly compressed Flora of New South Wales: Inflorescence 1-2.5cm across ovary notched A. nahui: Spikes 5-7mm diam ovary… compressed
SMALL FLOWERS LARGE FLOWERS Very plastic – how good are quantitative characters?
One of these things is not like the others….
A. nodiflora in Africa / Asia
Where to next? Source material from South Africa Compare ITS data and morphology If we find A. nahui is cosmopolitan / weedy, can we release other Alligator weed agents?
Acknowledgements National Biocontrol Collective, MSI Beating Weeds II Dagmar Goeke, Ana Ramon-Laca, Diana Prada Shon Scholer, CSIRO Brisbane John Hoskings, NSW Department of Industry Jenny Dymock, Wendy Mead