Repeated Evolution of Dioecy from Monoecy in Siparunaceae (Laurales)

Siparunaceae comprise Glossocalyx with one species in West Africa and Siparuna with 65 species in the neotropics; all have unisexual flowers, and 15 species are monoecious, 50 dioecious. Parsimony and maximum likelihood analyses of combined nuclear ribosomal ITS and chloroplast trnL-trnF intergenic spacer sequences yielded almost identical topologies, which were used to trace the evolution of the two sexual systems. The African species, which is dioecious, was sister to all neotropical species, and the monoecious species formed a grade basal to a large dioecious Andean clade. Dioecy evolved a second time within the monoecious grade. Geographical mapping of 6,496 herbarium collections from all species sorted by sexual system showed that monoecy is confined to low-lying areas (altitude < 700 m) in the Amazon basin and southern Central America. The only morphological trait with a strong phylogenetic signal is leaf margin shape (entire or toothed), although this character also correlates...

杯轴花科（Siparunaceae）包含Glossocalyx属（仅含1种，分布于西非）与Siparuna属（65种，分布于新热带区）；该科所有类群均具单性花，其中15种为雌雄同株，50种为雌雄异株。针对核核糖体ITS序列与叶绿体trnL-trnF基因间隔区的联合序列开展简约法与最大似然法分析，得到了几乎一致的拓扑结构，并基于此追溯了两种有性系统的演化历程。其中该非洲雌雄异株物种为所有新热带区类群的姊妹群，而雌雄同株类群构成一个演化级，位于一个大型雌雄异株安第斯演化支的基部。雌雄异株性状在该雌雄同株演化级中发生了第二次独立起源。对按有性系统分类的全部物种的6496份标本馆馆藏标本开展地理分布制图后发现，雌雄同株类群仅分布于亚马孙盆地与中美洲南部的低海拔区域（海拔<700米）。唯一具有强系统发育信号的形态性状为叶缘形状（全缘或具齿），尽管该性状同时与……