Golden everlasting paper daisies (Xerochrysum, Gnaphalieae, Asteraceae) were some of the earliest Australian native plants to be cultivated in Europe. Reputedly a favourite of Napoléon Bonaparte and Empress Joséphine, X. bracteatum is thought to have been introduced to the island of St Helena in the South Atlantic during Napoléon’s exile there. Colourful cultivars were developed in the 1850s, and there is a widely held view that these were produced by crossing Xerochrysum with African or Asian Helichrysum spp. Recent molecular phylogenetic analyses and subtribal classification of Gnaphalieae cast doubt on this idea. Using single-nucleotide polymorphism (SNP) data, we looked for evidence of gene flow between modern cultivars, naturalized paper daisies from St Helena and four Xerochrysum spp. recorded in Europe in the 1800s. There was strong support for gene flow between cultivars and X. macranthum. Paper daisies from St Helena were genotypically congruent with X. bracteatum and showed no indications of ancestry from other species or from the cultivars, consistent with the continuous occurrence of naturalized paper daisies introduced by Joséphine and Napoléon. We also present new evidence for the origin of colourful Xerochrysum cultivars and hybridization of congeners in Europe from Australian collections.

中文翻译：

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通过历史追溯杂交种的起源：巨大的栽培品种和拿破仑·波拿巴的流放纸雏菊（菊科；Gnaphalieae）

金色永生纸雏菊（Xerochrysum、Gnaphalieae、菊科）是最早在欧洲种植的澳大利亚本土植物。据说是拿破仑波拿巴和约瑟芬皇后的最爱，X. bracteatum 被认为在拿破仑流放期间被引入南大西洋的圣赫勒拿岛。五颜六色的栽培品种是在 1850 年代开发的，人们普遍认为这些栽培品种是通过将 Xerochrysum 与非洲或亚洲 Helichrysum spp 杂交而产生的。最近对 Gnaphalieae 的分子系统发育分析和亚部落分类对这一想法提出了质疑。使用单核苷酸多态性 (SNP) 数据，我们寻找现代栽培品种、来自圣赫勒拿岛的归化纸雏菊和四种 Xerochrysum spp 之间基因流动的证据。1800 年代在欧洲记录。强烈支持品种与 X. macranthum 之间的基因流动。来自圣赫勒拿的纸雏菊在基因型上与 X. bracteatum 一致，并且没有显示出来自其他物种或栽培品种的祖先迹象，这与约瑟芬和拿破仑引入的归化纸雏菊的持续出现一致。我们还提供了新的证据，证明五颜六色的 Xerochrysum 品种的起源和来自澳大利亚收藏的欧洲同系物的杂交。