A New Pollen Aperture in Schleichera oleosa (Lour.) Oken from Madhya Pradesh, Central India, and its Taxonomic and Evolutionary Significance

Angiosperms demonstrate a surprisingly frequent phenomenon of variability in the gross pollen morphological characteristics. In thepresent study, we recorded and described a new aperture in the pollen grains of Schleichera oleosa (Lour.) Oken, a monotypic genusof the soapberry family Sapindaceae, from Madhya Pradesh, central India, based on the LM and CLSM observations. This condition istermed the tetra-zono-parasyncolporoidate condition. A new pollen aperture has been recorded in this monotypic genus with theusual one (tri-zono-parasyncolporoidate condition), and this phenomenon of the occurrence of a new with increased number of pollenaperture is known as pollen aperture heteromorphism. The study will further help identify this taxon from the sedimentary archives asone of the indicators of the warm and humid (moist) climate and increased monsoonal rainfall.