Populus deltoides - <i><a href="//commons.wikimedia.org/wiki/Populus_deltoides" title="Populus deltoides">Populus deltoides</a></i> subsp. <i>monilifera</i> mature trees, along the Arkansas River in south-central Colorado, USA. © Dave Powell, USDA Forest Service - CC BY 3.0 us - Wikimedia Commons
Grotte de Hautecourt