Abstract Plant checklists constitute the fundamental knowledge on which further hypotheses of ecology, evolution, and biodiversity conservation are built. Here, we compiled a comprehensive and taxonomically verified checklist of the flowering plant species occurring in the Caatinga. We circumscribe Caatinga to include only the dry deciduous vegetation in Northeast Brazil, corresponding to the largest continuous nucleus of the seasonally dry tropical forest and woodland biome (SDTFW) in South America. We recorded 3347 species, 962 genera, and 153 families, of which 526 species and 29 genera are endemic, and the large contribution of its non-woody component to overall diversity. These numbers reveal a remarkably high floristic diversity in the Caatinga, representing almost two fold higher species/area ratio (4.0 × 10−3 species/km2) as compared to the Amazon rainforests (2.5 × 10−3 species/km2). Most Caatinga-inhabiting species are shared with other non-SDTFW tropical biomes, probably reflecting transition zones with surrounding savannas and rain forests. This newly assembled taxonomic checklist is expected to serve not only as an updated look at the identity and counting of the Caatinga plant diversity, but will also provide aids for better understanding the origin, evolution, and ecological function of this species-rich, but highly threatened South American vegetation.

中文翻译：

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巴西卡廷加季节性干燥森林和林地的最新植物清单显示物种丰富度和特有性很高

摘要 植物清单构成了进一步构建生态、进化和生物多样性保护假设的基础知识。在这里，我们编制了一份经过分类验证的综合性卡廷加开花植物种类清单。我们将卡廷加限定为仅包括巴西东北部的干燥落叶植被，对应于南美洲季节性干燥热带森林和林地生物群落 (SDTFW) 的最大连续核心。我们记录了 3347 种、962 属和 153 科，其中 526 种和 29 属是地方性的，并且其非木质成分对整体多样性的贡献很大。这些数字表明卡廷加的植物区系多样性非常高，几乎高出两倍的物种/面积比 (4. 0 × 10−3 种/平方公里），而亚马逊雨林（2.5 × 10−3 种/平方公里）。大多数居住在卡廷加的物种与其他非 SDTFW 热带生物群落共享，可能反映了与周围稀树草原和热带雨林的过渡区。这份新汇编的分类清单预计不仅可以作为对卡廷加植物多样性身份和计数的最新研究，而且还将有助于更好地了解这种物种丰富但高度依赖的起源、进化和生态功能。威胁南美植被。