Webwe discuss the various ways in which flower size and floral organ size can be modified, the means by which flower shape and symmetry can change, and the. Webthis chapter examines the origin of the flowering plants, and then looks in detail at those first flowers, considering their morphology, their development, and their diversification. Webtopics are the contingency of the primary morphological surface of the flower, the sequence of the origin of floral organs in evolutionary history (organ categories,.