Character evolution in Anaxagorea (Annonaceae)
Character evolution in Anaxagorea (Annonaceae)
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DOI：
10.3732/ajb.93.1.36
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发表时间：
2006
影响因子：
3
通讯作者：
T. Scharaschkin;J. Doyle
中科院分区：
文献类型：
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作者：
T. Scharaschkin;J. Doyle
Anaxagorea是了解番荔枝科形态进化的一个关键属，因为它与其他木兰目植物具有多种特征，这些特征被解释为相对于其他番荔枝科的原始特征。我们提出了一个详细的讨论形态特征的结合形态学和分子系统发育分析的Anaxagorea，沿着的影响，属的字符进化的分析。尽管在雄蕊和叶片脉序特征的高度同质性，他们的删除结果在获得的树木的分辨率损失。树上特征的分布证实了以下假设，即Anaxagorea和其他木兰目之间的几个明显相似之处是原始保留（例如，在中脉中存在木质部的正面板，非盾形雄蕊药隔，内部退化雄蕊和几个叶结构特征）。然而，横向延伸的“层状”雄蕊，虽然可能是祖先在Anaxagorea，收敛与其他木兰目。已经鉴定了包含大多数中美洲物种的一个进化枝和包含所有亚洲物种的另一个进化枝的许多形态学共形（例如，中美洲分支具圆锥形芽和退化的内花瓣，亚洲分支具正面角质条纹和头状柱头）。
Anaxagorea is a critical genus for understanding morphological evolution in Annonaceae because it shares a variety of features with other Magnoliales that have been interpreted as primitive relative to other Annonaceae. We present a detailed discussion of morphological characters used in a combined morphological and molecular phylogenetic analysis of Anaxagorea, along with implications of the analysis for character evolution in the genus. In spite of a high level of homoplasy in stamen and leaf venation characters, their removal results in loss of resolution in the trees obtained. The distributions of characters on trees confirm assumptions that several distinctive similarities between Anaxagorea and other Magnoliales are primitive retentions (e.g., the presence of an adaxial plate of xylem in the midrib, nonpeltate stamen connectives, inner staminodes, and several leaf architectural characters). However, lateral extensions of the "laminar" stamens, though possibly ancestral in Anaxagorea, are convergent with those in other Magnoliales. A number of morphological synapomorphies have been identified for a clade containing most Central American species and another comprising all Asian species (e.g., conical bud shape and reduced inner petals for the Central American clade, and adaxial cuticular striations and capitate stigma shape for the Asian clade).