American Journal of Botany Advertisement 30-1-2020 American Journal of Botany / Volume 106, Issue 6 Research Article The monocotyledonous underground: global climatic and phylogenetic patterns of geophyte diversity Cody Coyotee Howard , Ryan A. Folk , Jeremy M. Beaulieu , Nico Cellinese First published: 20 May 2019 https://doi.org/10.1002/ajb2.1289 Citations: 2 Abstract Premise Geophytes—plants that typically possess a bulb, corm, tuber, and/or rhizome—have long captured the attention of hobbyists and researchers. However, despite the economic and evolutionary importance of these traits, the potential drivers of their morphological diversity remain unknown. Using a comprehensive phylogeny of monocots, we test for correlations between climate and geophyte growth form to better understand why we observe such a diversity of underground traits in geophytes. Understanding the evolutionary factors promoting independent origins of these potentially adaptive organs will lend insights into how plants adapt to environmental hardships. Methods Using a comprehensive phylogeny incorporated with global occurrence and climate data for the monocots, we investigated whether climatic patterns could explain di erences between geophytes and non‐geophytes, as well as di erences among bulbous, cormous, tuberous, rhizomatous, and non‐geophytic taxa. We used phylogenetically‐informed ANOVAs, MANOVAs, and PCAs to test di erences in climatic variables between the di erent growth forms. Results Geophytes inhabit cooler, drier, and more thermally variable climates compared to non‐ geophytes. Although some underground traits (i.e., bulb, corm, and tuber) appear to https://bsapubs.onlinelibrary.wiley.com/doi/abs/10.1002/ajb2.1289 1/4 30-1-2020 American Journal of Botany inhabit particular niches, a result supported by strong phylogenetic signal, our data has limited evidence for an overall role of climate in the evolution of these traits. However, temperature may be a driving force in rhizome evolution, as well as the evolution of taxa which we considered here as non‐geophytic (e.g., trees, epiphytes, etc.). Conclusions While precipitation patterns have played a role in the evolution of geophytism, our results suggest that temperature should be more strongly considered as a contributing factor promoting the evolution of belowground bud placement, speci cally in rhizomatous and non‐geophytic taxa. Bulbous, cormous, and tuberous taxa need closer examination of other mechanisms, such as anatomical constraints or genetic controls, in order to begin to understand the causes behind the evolution of their underground morphology. Citing Literature Supporting Information Filename Description ajb21289- APPENDIX S1. Taxonomic classi cation (order, family and species columns) for all 12,779 sup-0001- taxa in addition to growth form coding (geophyte column) with references (reference Appendix column) used to infer character state. Numbers used for coding are 0 (bulb), 1 (corm), 2 S1.csv (rhizome), 3 (tuber), and 4 (non‐geophyte). For list of references used for character coding, CSV see Appendix S2 . document, 590.1 KB https://bsapubs.onlinelibrary.wiley.com/doi/abs/10.1002/ajb2.1289 2/4 30-1-2020 American Journal of Botany Filename ajb21289- Description APPENDIX S2. Sources used for the character coding of geophytes found in Appendix S1 . sup-0002- Citation numbers correspond to the reference used to code each taxon (see reference Appendix column in Appendix S1 ). S2.docx Word document, SOCIETY INFORMATION RESOURCES ADVERTISING & PERMISSIONS © 2020 Botanical Society of America About Wiley Online Library Privacy Policy Terms of Use Cookies Accessibility Help & Support https://bsapubs.onlinelibrary.wiley.com/doi/abs/10.1002/ajb2.1289 3/4 30-1-2020 American Journal of Botany Contact Us Opportunities Subscription Agents Advertisers & Corporate Partners Connect with Wiley The Wiley Network Wiley Press Room Copyright © 1999-2019 John Wiley & Sons, Inc. All rights reserved https://bsapubs.onlinelibrary.wiley.com/doi/abs/10.1002/ajb2.1289 4/4