Thus wrote Charles Darwin to his friend Joseph Hooker in 1853, taunting him about the ability of plants to disperse across wide stretches of ocean, and the floristic connections between the southern continents. The present distribution of species and the composition of island floras formed an important part of Darwin’s evidence for the Origin of Species by Means of Natural Selection (1859), and thus lies at the roots of our understanding of historical biogeography. Argument between "diffusionists" and "bridge-builders" dominated biogeographical debate for more than a century, and although muted since the acceptance of plate tectonics, these debates continue. Outside New Zealand and southern Chile, Kowhai (Sophora microphylla = Edwardsia) has an insular range as a native species. Some seeds collected in 1955 on Gough Island (S.Atlantic) floated in water for three years, and were then germinated by Dr Eric Godley at Lincoln.

Experiments with 1000 empty bottles jettisoned in Drake Passage and the far SW Atlantic from 1977 to 1991 resulted in 15 stranding on beaches in South Africa (1), Seychelles (1), mainland Australia (5), Tasmania (2), New Zealand (4), Easter Island (1) and Chile (1). Times between launching and recoveries confirms what is known of drift rates in the Antarctic Circumpolar Current. The bottle recovery sites are compared to the natural range of Kowhai

Systematic beachcombing of the 26km strand at Anxious Bay on Eyre Peninsula in South Australia showed that the beach is visited by foxes, cats and rodents living in the dunes and scavenging along the strandlines at night. This suggests that plants with buoyant seeds, such as Kowhai which appear to have a preference for growing on oceanic islands, may owe their natural ranges in part to the absence of such animals in island faunas. Details of beachcombing at Anxious Bay 1991 can be seen at

http://www.sardi.sa.gov.au/aquatic/aquatic/communit.htm