First Place: All's Fair in Love and War

A glimpse at the reproductive and putatively defensive structures of Richardia grandiflora - This image captures a dark field view of the stigma of Richardia grandiflora (Mexican clover – a common weedy plant of S. Florida lawns). The stigma is part of the floral organ responsible for receiving pollen and for female reproductive success. At the center of the stigma, bright green calcium oxalate crystals are visible, arranged as large raphide bundles (groups of needle-like formations) and druses (small, rounded crystal clusters with sharp protrusions) that refract light in a striking display. These crystals, composed of the same compound as kidney stones, are produced by many plants as a metabolic byproduct and can deter chewing herbivores. One current project in the Francis Pollination Ecology Lab at FAU investigates the ecological consequences of variation in these crystal structures across tissues and populations of R. grandiflora.

On the outer surface of the stigma, magenta pollen grains, stained with Basic Fuchsin for contrast, stand out sharply. Some grains have already germinated, sending pollen tubes toward the ovules to fertilize and produce seeds. Each pollen grain carries male genetic material, and its successful journey from the stigma to an ovule is crucial for the plant’s male component reproductive success. In this image, we can see many pollen grains competing to germinate, release their genetic contents, and sire the next generation.

The clarity and depth in this image are achieved through a focus stack of nine images, revealing the intricate details of R. grandiflora’s reproductive and defensive strategies at a microscopic level.