Botany, Ahead of Print.
The Syagrus glaucescens complex comprises three species: Syagrus glaucescens Glaz. ex Becc., Syagrus duartei Glassman, and Syagrus evansiana Noblick. Recently, a new population of S. evansiana that possesses a high degree of endemism was reported in the Serra do Cabral mountain. Here we intend to study the leaf anatomy of the S. glaucescens complex and confirm whether this newly found population (from now on called Syagrus aff. evansiana) belongs to S. evansiana or not. Specimens were collected to investigate their leaf anatomy, which showed distinct differences between S. aff. evansiana and S. evansiana. The midrib anatomy revealed novelties for the S. glauscecens complex, proving useful for species diagnosis. Features such as accessory vascular bundles around the vascular system of the midrib and the number of collateral bundles are diagnostic for species identification. In addition, morphological and anatomical analyses indicated a correlation with the species occurrence. We found greater similarity between S. glaucescens and S. duartei, while S. evansiana and S. aff. evansiana are more alike. Here, we propose a new identification key based only on the leaf anatomy. Despite their morphological similarities, S. aff. evansiana and S. evansiana presented differences in leaf anatomy, which — when associated with their geographical isolation — suggests a fourth taxon in the complex.

中文翻译：

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使用叶解剖重新评估 Syagrus glaucescens complex (Arecaceae) 的物种边界

植物学，超前印刷。
Syagrus glaucescens 复合体包括三个物种： Syagrus glaucescens Glaz。前 Becc.、Syagrus duartei Glassman 和 Syagrus evansiana Noblick。最近，在 Serra do Cabral 山报道了一个具有高度特有性的新种群 S. evansiana。在这里，我们打算研究 S. glaucescens complex 的叶子解剖结构，并确认这个新发现的种群（从现在起称为 Syagrus aff. evansiana）是否属于 S. evansiana。收集标本以研究它们的叶子解剖结构，这表明 S. aff 之间存在明显差异。evansiana 和 S. evansiana。中脉解剖揭示了 S. glauscecens 复合体的新颖性，证明对物种诊断很有用。中脉血管系统周围的辅助维管束和侧支束的数量等特征是物种识别的诊断依据。此外，形态学和解剖学分析表明与物种发生的相关性。我们发现 S. glaucescens 和 S. duartei 之间有更大的相似性，而 S. evansiana 和 S. aff。埃文西亚纳更相似。在这里，我们提出了一种仅基于叶解剖结构的新识别密钥。尽管它们的形态相似，S. aff。evansiana 和 S. evansiana 在叶解剖结构上存在差异，这与它们的地理隔离相关联时表明该复合体中存在第四个分类群。glaucescens 和 S. duartei，而 S. evansiana 和 S. aff。埃文西亚纳更相似。在这里，我们提出了一种仅基于叶解剖结构的新识别密钥。尽管它们的形态相似，S. aff。evansiana 和 S. evansiana 在叶解剖结构上存在差异，这与它们的地理隔离相关联时表明该复合体中存在第四个分类群。glaucescens 和 S. duartei，而 S. evansiana 和 S. aff。埃文西亚纳更相似。在这里，我们提出了一种仅基于叶解剖结构的新识别密钥。尽管它们的形态相似，S. aff。evansiana 和 S. evansiana 在叶解剖结构上存在差异，这与它们的地理隔离相关联时表明该复合体中存在第四个分类群。