The monocotyledonous underground: global climatic and phylogenetic patterns of geophyte diversity

Geophytes—plants typically with a bulb, corm, tuber or rhizome—are economically and evolutionarily important; however, the drivers of their morphological diversity remain unknown. Using a comprehensive phylogeny of monocots, we test for correlations between climate and growth form to better understand why we observe such a diversity of geophyte underground traits. Understanding the evolutionary factors promoting independent origins of these organs will lend insights into how plants adapt to environmental hardships. Using a phylogeny incorporated with global occurrence and climate data for the monocots, we investigated whether climatic patterns could explain differences between geophytes and non-geophytes, as well as differences among bulbous, cormous, tuberous, rhizomatous, and non-geophytic taxa. We used phylogenetically-informed ANOVAs, MANOVAs and PCAs to test differences in climatic variables between growth forms. Geophytes inhabit cooler, drier and thermally variable climates compa...