What is "sympetalae"

Sympetalae Rchb. (1828), meaning “with fused petals”, is a descriptive botanical name used in the Eichler, Engler, and Wettstein systems for a group in the flowering plants. In this group the flowers have a separate calyx and corolla with the petals fused, at least at the base of the corolla, a condition known as sympetaly.

Prior to the phylogenic classifications of August Eichler and his successors this group corresponds to the Gamopetalae of Bentham and Hooker In Eichler's Bluthendiagramme, Sympetalae, also classified as Metachlamydeae, was listed as a subclass of the class Dicotyleae, in contrast to the Choripetalae. Adolf Engler and Karl Prantl also listed Sympetalae as a division of the class Dicotyledoneae in their system, Die Naturlichen Pflanzenfamilien, with Sympetalae being composed of gamopetalous families Alfred Rendle similarly Sympetalae originated from dicots, and then divided Sympetalae into Pentacyclicae and Tetracyclicae in accordance with the number of flower parts in each group.

According to Engler and Prantl, Sympetalae includes the following orders: Diapensiales, Ericales, Primulales, Plumbaginales, Ebenales, Contortae, Tubiflorae, Plantaginales, Rubiales, Cucurbitales, and Campanulatae. This group corresponds closely to the Asteridae in the Cronquist system and to the asterids in the APG II-system.