Giant Amazonian lily pads are the world’s largest and strongest floating plants. Yet how the lily’s leaves are able to grow as large as 10 feet across, strong enough to support the weight of a small child, has remained a mystery—until now
, the deputy director of the Botanic Garden & Arboretum at the University of Oxford, calls “a big botanical enigma” into a guide that could inspire better engineering and design in buildings, particularly in floating structures.
“When we pull the leaves out of the pond here, and the public see them, they actually gasp at the beauty of the leaves,” Thorogood says. “They're astonishingly beautiful.” But it became more than a symbol as botanists repeatedly attempted to cultivate it in captivity. “It was an obsession,” writes Tatiana Holway in her book,. “Absorbing some of the most eminent and enterprising men of the Victorian era, the effort to retrieve this peerless exotic from the equatorial wilds where it grew and to cultivate it in England became an epic quest that captivated the world.”
Paxton had an intuitive grasp of the lily’s strengths—but only now have Thorogood and his colleagues worked out the mechanical details.Dressed in waterproof waders, the researchers climbed inside the large, heated pond at the Oxford University Botanic Garden to experimentally measure how the leaves respond to weight.Finn Box
“Once a leaf is submerged then it’s going to lose its space at the surface where it can photosynthesize,” Box says. With a camera, they recorded how much each leaf was indented and deformed when they pressed on it or placed a weight on it. Such stress tests showed that the Amazonian water lily leaves were orders of magnitude stiffer, and consequently stronger than the smaller leaves found on other, more commonplace lily species.