Ubisch bodies, con-peito grains) are small acellular structures of sporopollenin that might occur on the inner tangential and radial walls of tapetal cells.
In 1865, Rosanoff published observations on anthers of Fabaceae species in which he noticed small granules on the inner locule wall that were resistant to concentrated sulphuric acid.
[2][3] Von Ubish concluded that orbicules are homologous with the pollen exine, as both showed the same reaction to chemicals and stains and they developed synchronously.
[8][10][11] Orbicules are resistant to acetolysis and react to histochemical staining in a similar way as the pollen exine, indicating that they are composed of sporopollenin.
[4] Orbicules originate as lipid droplets (i.e. pro-orbicules) within the cytoplasm of tapetal cells, most likely from the rough endoplasmic reticulum.