Genetic data confirm the presence of <i>Senecio madagascariensis</i> in New Zealand

The <i>Senecio inaequidens</i> – <i>S. madagascariensis</i> complex (Asteraceae: Senecioneae, subsequently “fireweed complex”) is a group of six southern African species of <i>Senecio</i>, three of which are considered invasive in various parts of the world: <i>S. madagascariensis</i> in South America, Japan, Australia, and the Hawaiian Islands, <i>S. skirrhodon</i> in New Zealand, and <i>S. inaequidens</i> in Mexico and Europe. Morphological plasticity and historically limited access to reliable information in the introduced ranges have led to taxonomic confusion in many countries, where the weedy populations have been classified under changing names and sometimes erroneously considered to be native species. This confusion has hampered research into management options such as biological control. Recently, uncertainty has arisen about whether only one or two species of the fireweed complex are present in New Zealand. To resolve this question and test the utility of multi-locus sequence capture data for the understanding of the complex, we produced a first dataset of hundreds of genes for four of its species with a focus on <i>S. madagascariensis</i> and <i>S. skirrhodon</i>. Both species were found to be present in the North Island of New Zealand, with <i>S. madagascariensis</i> widespread in the Northland region and <i>S. skirrhodon</i> present at both sites sampled in the southern half of North Island. Our results show that sequence capture data provide high levels of confidence and resolution even at shallow phylogenetic levels, which will enable a greater understanding of the fireweed complex and its invasion history as the dataset is expanded.长根千里光（*Senecio inaequidens*）– 马达加斯加千里光（*S. madagascariensis*）复合群（菊科（Asteraceae）千里光族（Senecioneae），后文简称“火草复合群”）是一类包含6种南非产千里光属（*Senecio*）植物的类群，其中3种已在全球多地被列为入侵物种：马达加斯加千里光入侵南美、日本、澳大利亚及夏威夷群岛，斯氏千里光（*S. skirrhodon*）入侵新西兰，长根千里光入侵墨西哥与欧洲。形态可塑性以及历史上入侵区域内可靠信息获取的局限性，导致多国出现分类学混乱：这些杂草种群曾被冠以不断变更的学名，有时甚至被错误地认定为本土物种。这种分类混乱阻碍了包括生物防治在内的防控策略相关研究。近期，学界对新西兰境内仅存在火草复合群中的1个还是2个物种存在争议。为解决这一问题并验证多位点序列捕获（multi-locus sequence capture）数据在解析该复合群分类关系中的效用，本研究首次生成了覆盖该复合群4个物种的数百个基因数据集，研究重点聚焦于马达加斯加千里光与斯氏千里光。研究发现，新西兰北岛同时存在这两个物种：马达加斯加千里光广泛分布于北地大区，斯氏千里光则在北岛南部的两个采样点均有发现。研究结果表明，即便在较浅的系统发育层级上，序列捕获数据也能提供极高的支持度与分辨率；随着数据集不断扩充，该数据将助力学界更深入地解析火草复合群及其入侵历史。