Pollen grains are the male gametes in plants. It is present on the anthers. Pollen grains finds its way to the ovule by the process of pollination. The structure of pollen grains vary from one species of flower to another. The hibiscus and spider lily both have circular pollen grain.
However, the atomic structure of pollen grain of hibiscus represents the Buckminster fullerene but is not shown in spider lily. The pollen grains of hibiscus have spikes on its surface.
The answer to that would be archaebacteria since they are prokaryotes (no nucleus) but so is Eubacteria, however archaebacteria can live in very harsh conditions.
