Oxalis pollen. Coloured scanning electron micrograph (SEM) of Oxalis triangularis pollen. Oxalis triangularis commonly called false shamrock, is a species of perennial plant in the family Oxalidaceae. It is native to several countries in southern South America. This wood sorrel is typically grown as a houseplant. Pollen grains are the male sex cells of a flowering plant. Their characteristic surface is used by botanists to recognise and classify plants. Pollen in plants is used for transferring male genetic material from the anther of a single flower to the stigma of another in cross-pollination. In a case of self-pollination, this process takes place from the anther of a flower to the stigma of the same flower. Magnification: x800 when printed at 10cm wide.