Ultrathin seed wing with heterogeneous structures for highly efficient dispersal of African tulip tree.

To colonize new habitats, plant seeds have evolved a variety of specialized structures for wind dispersal. The African tulip tree, identified as one of the world's 100 worst invasive alien species, features filmy winged seeds predominantly dispersed by wind. Herein, we found that most of the wing region is single-cell-layer thick with the thinnest part measuring only 0.4 μm, enabling the wing to cover 90% of the seed's size while constituting only 25% of the total mass. We revealed that such an ultrathin wing is reinforced by a series of heterogeneous vein-like structures that maintain the wing extension even in turbulent airflow and can resist circumferential fracture to minimize detrimental impacts on aerodynamic performance. The filmy wing is also able to conformably attach to uneven wet substrates, enhancing the chance of locating on water-rich soils for seed germination. The unique geometry and material composition in the seed wing present an elegant natural solution in balancing light weight, proper stiffness, and directional toughness suited for varied environments. Inspired by the natural seed, we designed a passive micro-flier with a customizable wing that can realize multiple functions, illuminating new possibilities in large-scale aerial delivery for wide-range sampling and environmental monitoring.