How flowers catch raindrops

TL;DR

This study investigates how certain plants use raindrop impacts on their flowers to disperse seeds over long distances, using high-speed videography and 3D-printed mimics to optimize flower shapes for maximum seed dispersal.

Contribution

The paper introduces a fluid dynamics analysis of seed dispersal by raindrop impacts, highlighting the effectiveness of off-center impacts and optimized flower geometries.

Findings

Off-center impacts enhance seed dispersal distance.

Optimized flower shapes increase seed propulsion efficiency.

Raindrop impact dynamics can be manipulated for better seed dispersal.

Abstract

Several species of plants have raindrop-sized flowers that catch raindrops opportunistically in order to spread their 0.3-mm seeds distances of over 1 m. In the following fluid dynamics video, we show examples of these plants and some of the high speed videography used to visualize the splash dynamics responsible for raindrop-driven seed dispersal. Experiments were conducted on shape mimics of the plants' fruit bodies, fabricated using a 3D printer. Particular attention was paid to optimizing flower geometries and drop impact parameters to propel seeds the farthest distance. We find off-center impacts are the most effective for dispersing seeds. Such impacts amplify the raindrop's speed, encapsulate seeds within drops, and direct the seed trajectory at angles optimal for long-distance dispersal.