Contents

01 September 2017
Vol 357, Issue 6354

About The Cover

COVER A woman grips a giant Monstera leaf, a common plant genus of the American tropics. Leaf size varies enormously with differences in air temperature, light, and soil moisture, which affect the possibility of leaves overheating during the day or suffering frost damage at night. Thus, hot deserts and cold high-elevation sites are characterized by small-leaved species, whereas plants in warm rainforests tend to have larger leaves. See page 917.
Photo: Mark Notari/Getty Images