The family has about 42 genera and up to 700 species.
It is divided into subfamilies then tribes and subtribes.
It contains a number of plants commonly known as Wandering Jew.
Some of the better known genera are Commelina, Callisia, Cyanotis, Dichorisandra and Tradescantia.
Australia has 25 species of the family spread over 9 genera.
Many are grown as house or garden plants and many are environmental weeds.
They are mostly perennial with stems that creep along the ground or scramble over things.
Roots are fibrous and the stems often fleshy.
Stems are often swollen at the nodes from which roots can grow.
The stems break easily at the nodes.
The alternate, often semi-fleshy leaves can be in 2 ranks or a spiral.
Their bases sheath the stem and the sheath edges are joined to completely surround the stem.
There are often hairs on the top of the sheath.
Veins are parallel.
Inflorescences, terminal or axillary, are sometimes enclosed in a leaf or spathe-like bract.
Most species have bisexual flowers but some have male flowers as well.
There is a lot of variation in the features of the inflorescence and flowers within species.
Petals only last for 1 or 2 days.
The calyx has 3, usually green, sepals that are of equal size.
The corolla has 3 petals that can be blue, purple, white or rarely yellow.
Petals are usually free and sometimes the bases are very narrow (clawed).
One petal may be a smaller or a different colour.
Most have 6 stamens in 2 whorls and they may be of unequal lengths.
Up to 3 stamens may be infertile staminodes or not developed.
The filaments can be smooth or some or all may have hairs.
Anthers are basifixed or dorsifixed.
Pollen is released via longitudinal slits on the sides or through apical pores.
The ovary is superior with 3 carpels, 2 or 3 locules and 1 style.
Each locule has 1 to many ovules.
Fruit is typically a dry, dehiscent capsule.