Vaccine patch
Surface of a grass bud showing four stomata and a pollen grain that has fallen from a flower. Stomata are pores that open and close to control the flow of gases into and out of the leaf. They also let water out of the plant during transpiration. All the stomata are closed on this leaf.
Imaged using scanning electron microscopy by Dr Errin Johnson, University of Sydney.
Size: the pollen grain is 13 micrometres long.
