The Apocynaceae family has been, and is still occasionally seen as two families – the Apocynaceae or Dogbane family and Asclepiadaceae the Milkweed family.
Asclepiadaceae is now officially classified as the subfamily Asclepiadoideae in Apocynaceae.
Family Apocynaceae > Subfamily Asclepiadoideae > Tribe Marsdenieae.

There has been much debate over a long period about what genera should be included in the family and species have been moved between various genera.
The Stephanotis genus was included in Marsdenia for a while.
Currently there are 15 species in Stephanotis with 4 new species being described a few years ago.

Stephanotis are twining climbers with stems metres long.
Stems and leaves have a milky latex.
The simple ovate to elliptic leaves are opposite.

Axillary inflorescences are an umbel with flowers all attached to the end of the peduncle.
The scented flowers are mostly white but some species have white with pink or violet tints.
Flowers have 5 free sepals and the petals are fused into a funnel-shaped corolla tube with 5 lobes.

The 5 stamens have almost no filament and the anthers are fused to the large style head to form a gynostegium.
This is described and illustrated under Stephanotis floribunda.

The superior ovary has 2 locules with numerous ovules in each.
The fruit are paired follicles although one often aborts.
The seeds have a plume of silky hairs on one end.