SA was funded by the Fyssen Foundation. CJP was funded by a Marie Curie Postdoctoral Fellowship. XZ was funded by the Staff Development Programme of the Xishuangbanna Tropical Botanical Garden (XTBG), Chinese Academy of Sciences. OJL was funded by the Jenny and Antti Wihuri Foundation. LC was funded by an ERC Advanced Grant and a Royal Society Wolfson Research Merit Award. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript