Data from: Phylogenetic systematics of Cochlospermaceae (Malvales) based on molecular and morphological evidence

Cochlospermaceae (Malvales) is a small family of two genera, Amoreuxia and Cochlospermum. Cochlospermum has a pantropical distribution with species present in Mexico, Central and South America, the West Indies, Africa, India, Southeast Asia, and northern Australia, whereas Amoreuxia has a more restricted distribution in the Americas. Amoreuxia is comprised of four herbaceous species, and Cochlospermum has seven tree species and five that are suffrutescent subshrubs. The two genera also differ in floral symmetry, corolla coloration patterns, and stamen morphology. The goals of this study were to reconstruct the phylogeny of Cochlospermaceae to evaluate the monophyly of the family and its two genera, to resolve interspecific relationships, and to interpret patterns of morphological evolution. In addition, a minor goal was to examine its relationship to sister families, such as Bixaceae, a family in which Cochlospermaceae has been variously placed. Phylogenetic analyses were carried out using DNA sequences of the following markers: nuclear ribosomal ITS and the chloroplast trnG and trnL-F regions. The data support the monophyly of Cochlospermaceae and its distinctiveness from its sister families. While Amoreuxia is supported as monophyletic, Cochlospermum is paraphyletic with two species (C. orinocense and C. tetraporum) consistently placed outside a clade of all remaining Cochlospermum species. Ancestral character state reconstructions of morphology indicate that the tree habit may be ancestral in Cochlospermaceae with a single shift to an herbaceous growth form in Amoreuxia with the suffrutescent growth form having arisen twice within Cochlospermum, once in South America and once in Africa. There has been a single shift in floral morphology from radial symmetry, solid yellow petals, and uniform stamens to bilateral symmetry, two-toned petals, and dimorphic stamens in Amoreuxia. Anthers with one apical pore found in core Cochlospermum species may be a reduction from anthers with two pores, such as those found in Amoreuxia and in C. orinocense and C. tetraporum. Seed shape supports the sister relationships within Cochlospermaceae, particularly within Amoreuxia.

弯子木科（Cochlospermaceae）隶属于锦葵目（Malvales），是一个仅含2个属的小型植物类群，分别为安穆瑞木属（Amoreuxia）与弯子木属（Cochlospermum）。弯子木属呈泛热带分布，其物种见于墨西哥、中美洲、南美洲、西印度群岛、非洲、印度、东南亚及澳大利亚北部；而安穆瑞木属的分布范围更为局限，仅分布于美洲区域。安穆瑞木属包含4个草本物种，弯子木属则涵盖7个乔木物种与5个半灌木（suffrutescent subshrubs）物种。两属在花对称性、花冠花色模式及雄蕊形态上均存在显著差异。本研究的核心目标为重建弯子木科的系统发育框架，以评估该科及其两个属的单系性，解析属间与属内物种的系统发育关系，并阐释其形态演化规律。此外，本研究附带的次要目标为探讨弯子木科与其姐妹科的亲缘关系，例如红木科（Bixaceae）——该类群曾被不同分类学处理纳入弯子木科的归属范畴。本研究通过以下分子标记的DNA序列开展系统发育分析：核核糖体ITS区域，以及叶绿体trnG与trnL-F区域。分析结果支持弯子木科为单系类群，且其与姐妹科间存在明确分化。尽管安穆瑞木属被证实为单系类群，但弯子木属为并系类群，其中2个物种（C. orinocense与C. tetraporum）始终处于其余所有弯子木属物种构成的演化支之外。形态学祖先性状状态重建结果显示，乔木生长型可能为弯子木科的祖先性状，安穆瑞木属仅经历了1次从乔木到草本生长型的演化转变；而半灌木生长型在弯子木属内独立起源了2次，分别发生于南美洲与非洲。花部形态仅发生过1次关键演化转变：从辐射对称、纯色黄色花瓣、雄蕊整齐均一，转变为两侧对称、两色花瓣、雄蕊二型，该转变发生在安穆瑞木属中。核心弯子木属物种所具有的单顶孔花药，可能是由双孔花药（如安穆瑞木属以及C. orinocense与C. tetraporum的花药）演化而来的简化性状。种子形状特征可支持弯子木科内的姐妹群关系，尤其在安穆瑞木属内的物种亲缘关系解析中具有重要参考价值。