There are 9 (6 – 10) genera with about 200 (250) species.
Genera include Billardiera, Hymenosporum and Pittosporum which has 150 species.
Australia has about 42 species spread across 9 genera.
They are trees, shrubs, scramblers or lianas.
The evergreen leaves, mostly on petioles, are alternately arranged in spirals.
Sometimes they are clustered at the stem tips and look whorled.
The blades are simple and may have wavy or rarely, finely toothed edges.
Venation is pinnate with cross veins.
Inflorescences can be terminal or axillary, single flowers or clusters.
Each flower has 2 bracteoles. Most are bisexual and have flower parts in 5’s.
The sepals are usually free but sometimes have the bases loosely joined.
They fall of early.
The corolla usually has a tubular base with flaring terminal lobes.
The petal bases are typically free but may be loosely attached.
There are 3 to 5 veins on the lobes.
There are 5 stamens, all fertile, that alternate with the petals.
Stamens are usually free but sometimes loosely attached basally.
In flowers with a definite corolla tube the filaments may be partly fused to the petals.
Anthers, mostly dorsifixed, open inwards via slits or rarely, by apical pores.
The superior ovary is sometimes on a short stalk.
There are 2 (3 – 5) fused carpels with 1 (2 – 5 ) locules.
There are 1 to numerous ovules in each locule.
Placentation is mostly parietal.
Sometimes the placentas grow inwards and partially divide the ovary into more locules.
There is 1 apical style with a usually rounded stigma.
The fruit are berries or loculicidal capsules.
Hymenosporum differs from the other genera by having winged seeds.