Piperaceae is one of the 3 families in Order Piperales which is one of the basal angiosperms orders
    in the Magnoliids clade along with the Magnoliales, Canellales and Laurales.
Many are used for spices especially Piper nigra (peppercorns).
Australia has 2 genera with 12 species.

Plants can be vines or shrubs up to 4 m tall (Piper) or fleshy herbs up to 30 cm high (Peperomia).
They are terrestrial or epiphytic and some grow on rocks.
Crushed leaves have a spicy odour.
The stems may or may not branch and Piper has swollen nodes.

Petioles and stipules are usually present.
The often fleshy leaves are alternate, opposite or whorled.
Leaves are simple, venation pinnate or palmate.
The base is sometimes asymmetric.

Flowers are in spikes that are variously positioned.
The tiny flowers, have no perianth, usually no stalks but have small bracts.

Stamens vary from 1 to 10 but often in 2 sets of 3.
They can be free or joined at the base and the anthers open via longitudinal slits.

The ovary is superior and consists of 1 carpel in Peperomia and 3 or 4 in Piper.
It has one locule with 1 ovule.
There are 1 or 3 to 4 stigmas attached to the carpel or on a very short style.
Fruits are drupes or berries with 1 seed each.

The family has 5 genera, 3 with 10 species between them, plus Piper with about 2000
    species and Peperomia with about 1600.

Piper are shrubs or small trees, sometimes lianas, up to 4 m tall, with alternate leaves and flowers with 2 to 6 stamens.

Peperomia are fleshy herbs 10 to 30 cm high with variously arranged leaves and flowers with only 2 stamens.