@article{09b5e977544743cb80b500fde06504fa,
title = "Transitions between the terrestrial and epiphytic habit drove the evolution of seed-aerodynamic traits in orchids",
abstract = "Orchids are globally distributed, a feature often attributed to their tiny dustlike seeds. They were ancestrally terrestrial but in the Eocene expanded into tree canopies, with some lineages later returning to the ground, providing an evolutionarily replicated system. Because seeds are released closer to the ground in terrestrial species than in epiphytic ones, seed traits in terrestrials may have been under selective pressure to increase seed dispersal efficiency. In this study, we test the expectations that seed airspace—a trait known to increase seed flotation time in the air—is (i) larger in terrestrial lineages and (ii) has increased following secondary returns to a terrestrial habit. We quantified and scored 20 seed traits in 121 species and carried out phylogenetically informed analyses. Results strongly support both expectations, suggesting that aerodynamic traits even in dust seeds are under selection to increase dispersal ability, following shifts in average release heights correlated with changes in habit.",
keywords = "Dust seeds, Phylogenetic comparative methods, Seed airspace, Seed dispersal distance, Wind dispersal",
author = "Fan, {Xu Li} and Guillaume Chomicki and Kai Hao and Qiang Liu and Xiong, {Ying Ze} and Renner, {Susanne S.} and Gao, {Jiang Yun} and Huang, {Shuang Quan}",
note = "Funding Information: We thank the editor, Edmund D. Brodie III, and an anonymous reviewer for comments on the manuscript, the staff of the Xishuangbanna Tropical Botanical Garden for help in the field, and colleagues from the Orchid Society of China for providing material. This study was supported by the National Science Foundation of China (NSFC)–Yunnan jointed projects (U1402267, U1702235). G.C. is supported by a Glas-stone Research Fellowship in Science and a Junior Research Fellowship at Queen{\textquoteright}s College, both at the University of Oxford in the United Kingdom. Statement of authorship: J.-Y.G. and S.-Q.H. conceived this project; X.-L.F. and K.H. collected seed data; X.-L.F. made the scanning electron microscopy observations with help from Q.L.; X.-L.F., Y.-Z.X., and S.-Q.H. carried out initial statistical tests; G.C. carried out all comparative analyses; and G.C., S.-Q.H., and S.S.R. wrote the manuscript. Publisher Copyright: {\textcopyright} 2019 by The University of Chicago.",
year = "2020",
month = feb,
day = "1",
doi = "10.1086/706905",
language = "English",
volume = "195",
pages = "275--283",
journal = "American Naturalist",
issn = "0003-0147",
number = "2",
}