This book is a detailed analysis of seed characters of 65 taxa (61 species) belonging to 31 genera of tropical Acanthaceae based on light microscopy and electron microscopy. Founded on certain principles the present work also aims at evolving a uniform standard for describing angiosperm seeds in general; leading to a better understanding of the taxonomic and phylogenetic implications of the family. Utilising the parameters under study, a taxonomic key is also prepared for the taxa investigated. The examples provided here should project the potential for using seed morphology as a useful parameter not only in the studies of plant taxonomy and phylogeny but also as a reference standard wherever the study of seeds is relevant.