Napoleón's exile on St. Helena: Everlasting love and Australian paper daisies

Abstract

<p>The Australian and New Guinean everlasting paper daisy genus Xerochrysum, widely grown around the world as Strawflower, Everlasting or Immortelle, was recently revised. The first and type species, Xerochrysum bracteatum, was described in 1803 as Xeranthemum bracteatum from a plant cultivated in the Empress Joséphine's garden at Malmaison. During our project, we learned that Xerochrysum was naturalised in St. Helena, the place of Napoleón Bonaparte's last exile, and is presumed to have been introduced by him. We conducted genetic analyses to test the derivation of the St. Helena plants. Comparisons with some colourful hybrid cultivars and naturally occurring populations in Australia found the St. Helena plants to be most similar to Xerochrysum bracteatum s. str. of the Sydney Basin. The St. Helena plants were without admixture of another species as would be expected if they were more recently escaped ornamental cultivars. Our results support the conclusion that the St. Helena Xerochrysum were introduced during Napoleón's exile, likely as a reminder of his wife's garden.</p>