Data from: A first look at diversification of Beaksedges (tribe Rhynchosporeae: Cyperaceae) in habitat, pollination, and photosynthetic features

Tribe Rhynchosporeae (ca. 386 spp.; Cyperaceae) has high levels of endemicity (? 44%) in tropical and subtropical American savannas and can provide insights into the diversification of their biotas. Wind pollination, occupation of a savanna habitat, and a C3 photosynthetic pathway are common in the tribe, but showy (presumably insect-pollinated) inflorescences, occupation of forest habitat, and a C4 pathway also occur. We reconstructed a dated phylogenetic hypothesis for 79 taxa, inferring a mean crown-group age of 56 million years. Fitch parsimony infers the most recent common ancestor to have occupied a savanna habitat with eight or more shifts to forest. Features associated with insect pollination-white bracts and spikelets-were shown to evolve six or more times but werenot correlated with the shifts to forest habitat. We found evolutionary correlations in the pairwise comparisons of bract color versus spikelet color and bract positioning versus bract color. Members with anatomies associatedwith C4, photosynthesis though anatomically variable, form a clade with a crown age of 19 million years.

刺孢苔族（Rhynchosporeae）约含386个物种，隶属于莎草科（Cyperaceae），在美洲热带与亚热带稀树草原中具有极高的特有性（约44%），可为该区域生物群落的物种分化研究提供重要见解。该族类群普遍具有风媒传粉、稀树草原生境适配以及C3光合途径（C3 photosynthetic pathway）的特征，但也存在部分类群拥有艳丽的（推测为虫媒传粉的）花序、占据森林生境，且具备C4光合途径（C4 photosynthetic pathway）。本研究对79个分类单元重建了带时间校准的系统发育假说，推算得其冠群的平均起源年龄为5600万年。通过菲奇简约法（Fitch parsimony）分析，该族的最近共同祖先（most recent common ancestor）栖息于稀树草原生境，且至少经历了8次向森林生境的生态位转换。与虫媒传粉相关的特征——白色苞片与小穗——被证实至少演化了6次，但该特征与向森林生境的转换并无相关性。本研究还发现，在成对性状比较分析中，苞片颜色与小穗颜色、苞片着生位置与苞片颜色之间存在演化相关性。尽管解剖结构存在变异，但具有C4光合途径相关解剖特征的类群形成了一个冠群年龄为1900万年的单系支。