Studies on the palynology of Orchidaceae indicate that the pollen and polliniaria provide useful diagnostic features in supra-generic categories. Pollen grains are generally globose/ spheroidal in shape. Pollen grains may be boat-shaped, fusiform, triangular or ellipsoid. The pollen sizes are categorised based on the length of longest axis as very small, small, medium sized, large and very large. Apertures are specially delimited regions of the pollen grain wall through which pollen tubes emerge. The external features of the pollen grain wall are termed as pollen sculpturing. The pollen wall is designed to allow the pollen grain apertures to contract thus reducing the rate of water loss. Pollen unit refers to the number of pollen grains united together at the time of release. Pollen polarity is the spatial orientation of the pollen grains leading to the formation of two distinct poles which are observed at the tetrad stage.