''|alt=Ipomoea purga flowers '' |alt=Vaccinium corymbosum
Sympetalae Rchb. (1828), meaning "with fused
petals", is a
descriptive botanical name used in the
Eichler,
Engler, and
Wettstein systems for a group of
flowering plants (angiosperms). In this group the flowers have a separate
calyx and
corolla and in which the corolla
petals are fused, at least at their base, a condition known as sympetally. Prior to the
phylogenic classifications of
August Eichler and his successors this group corresponds to the
Gamopetalae of
Bentham and Hooker, gamopetally being a
synonym of sympetally. This was one of the three divisions of
dicotyledons in their system. In Eichler's
Blüthendiagramme, the class Dicotyleae was divided into two subclasses, the Sympetalae (also classified as Metachlamydeae) and the
Choripetalae.
Adolf Engler and
Karl Prantl also listed Sympetalae as a division of the class Dicotyledoneae in their system,
Die Natürlichen Pflanzenfamilien, with Sympetalae being composed of gamopetalous families having gamopetalous corollas.
Alfred Rendle similarly described Sympetalae as originating from
dicots, and then divided them into Pentacyclicae and Tetracyclicae in accordance with the number of flower parts in each group, four and five respectively. According to Engler and Prantl, Sympetalae includes the following orders:
Diapensiales,
Ericales,
Primulales,
Plumbaginales,
Ebenales, Contortae,
Tubiflorae,
Plantaginales,
Rubiales,
Cucurbitales, and
Campanulatae. Sympetalous flowers are found in many angiosperms, but it was the combination of sympetally with a "stamen whorl isomerous and alternate with the corolla-lobes, or stamens fewer than the corolla lobes" that
Takhtajan (1964) used to define the subclass
Asteridae, and later by
Cronquist (1981), and later, corresponding to the
asterids in the modern
Angiosperm Phylogeny Group (APG) system, based on
molecular phylogenetics. Since sympetally has arisen independently many times in evolution (
homoplasy), on its own it is not useful for
taxonomic classification. ==Examples==