Terminology
The flowers of angiosperms are determinate shoots that have sporophylls. The parts of flowers are named by scientists and show great variation in shape, these flower parts include sepals, petals, stamens and carpels. As a group the sepals form the calyx and as a group the petals form the corolla, together the corolla and the calyx is called the perianth. In flowers which possess indistinguishable calyx and corolla, the individual units are then called "tepals". The stamens collectively are called the androecium and the carpels collectively are called the gynoecium.
The complexity of the systems and devices used by plants to achieve sexual reproduction has resulted in botanists and evolutionary biologists using numerous terms to describe physical structures and functional strategies. Dellaporta and Calderon-Urrea (1993) list and define a variety of terms used to describe the modes of sexuality at different levels in flowering plants. This list is reproduced here, generalized to fit more than just plants that have flowers, and expanded to include other terms and more complete definitions.
Read more about this topic: Plant Sexuality