Let's pluck the daisy: dissection as a tool to explore the diversity of Asteraceae capitula

Asteraceae, the daisy family, are one of the most diverse families of angiosperms and are predominant in many ecosystems, including grasslands, deserts, savannas and high-elevation mountains. They are characterized by a peculiar inflorescence, the capitulum, which mimics a flower, but is actually made up of many tightly grouped florets. The capitulum is considered a key character underpinning the impressive evolutionary success of the family, and it plays a pivotal role in the economic importance of the family, given that many species are cultivated for their capitulum for agricultural and horticultural purposes. However, to date, there is still no comprehensive understanding of the extent of the morphological diversity of capitula across lineages of Asteraceae. This is mainly due to a lack of appropriate tools for describing such a complex and condensed structure. To address the problem, we present a protocol for characterizing the full diversity of capitula from any lineage of Asteraceae. This involves making a whole dissection of a capitulum from fresh material; it is simple and cost-effective and requires relatively easy-to-transport equipment meaning that it can be done during fieldwork.

This research was supported through a research grant by the Winton (Harding) Alpine Plant Conservation & Research Programme (WHAPCRP, https://www.winton.com/philanthropy), by the Lautaret Garden-UMS 3370 (University of Grenoble Alpes, CNRS, SAJF, 38000 Grenoble, France), member of AnaEE-France (ANR-11-INBS-0001AnaEE-Services, Investissements d’Avenir frame) and of the eLTER-Europe network (University of Grenoble Alpes, CNRS, LTSER Zone Atelier Alpes, 38000 Grenoble, France), the project ‘COMPOSITAE’ reference PID2020-116480GB-I00 funded by MCIN/AEI/10.13039/501100011033 and the ‘Ajuts a Grups de Recerca Consolidats’ (2017/SGR/1116) from the Generalitat de Catalunya. OH benefited from a Marie Skłodowska-Curie Action Individual Fellowship (grant agreement number 657918). JP benefited from a Ramón y Cajal grant reference number RYC-2017-2274 funded by MCIN/AEI/10.13039/501100011033 and by ‘ESF Investing in your future’.

Abstract INTRODUCTION MATERIAL AND METHODS NOTES SUPPORTING INFORMATION ACKNOWLEDGEMENTS REFERENCES Supplementary data