Alsomitra macrocarpa – also called the Javan Cucumber is a tropical plant growing on the Malay Archipelago and the Indonesian islands and is producing one of the most stunning (and largest) seeds.
The Javan Cucumber is a liana and reaches a length of 30-50 meters with a diameter of up to 15 centimeters. Also its fruits are large and can grow up to 30 cm in diameter. But the seeds are the most fascinating aspect of this plant. Each fruit contains hundreds of them. They have very large wings, which enable them to glide over long distances. The incredibly thin wings are flat bracts that are embedding the seed in its center. A bract is a specialized leaf that is associated with the flowering parts of a plant. Often, bracts are found as small leaves below the petals of a flower. The flight of the seeds has been fascinating humans for more than a hundred years. Not only because of its beauty – the seeds have been described to look like butterflies gliding through the trees – but also because of its physical properties.
The flight of the Alsomitra macrocarpa seeds shows incredible stability and a slow descent of only 0.3-0.7 m per second. This enables them to cross large distances. As seeds travel several hundred meters before falling to the ground and beginning to grow, they won’t compete with their parent plant for nutrients and space. Seeds with large wings, that help them glide over long distances, are relatively common in the plant kingdom. You’re probably already thinking of the winged seeds of maple, pine, linden, or hornbeam. Typically, these seeds auto-rotate while gliding, which is not the case for the Javan Cucumber seeds.
The seed is positioned at the center of gravity, between the two wings. This enables a forward position of the aerodynamic center and a flight without rotation. The stable flight has even been described as very efficient and as high-performance gliding and served as an inspiration for technological advances, such as the stable wing platform designed by the Austrian flight pioneers Ignaz and Igo Etrich in 1904.
See for yourself what is so fascinating about them:
Sources
Azuma, A., & Okuno, Y. (1987). Flight of a samara, Alsomitra macrocarpa. Journal of Theoretical Biology, 129(3), 263-274.
Silvertown, J. (2009). { 10 } Winged Seeds. DISPERSAL. In An Orchard Invisible (pp. 101-107). Chicago: University of Chicago Press.
Habib, M. K. (2011). Biomimetics: innovations and robotics. International Journal of Mechatronics and Manufacturing Systems, 4(2), 113. doi:10.1504/ijmms.2011.039263
Gbif.org/species/5537054
Wikipedia.org