Previously subfamily Phyllanthoideae in a loosely defined Euphorbiaceae family it is now mostly recognised as a family itself
although it is occasionally still seen in Euphorbiaceae.
Phyllanthaceae can be separated from Euphorbiaceae by having no latex, no extrafloral nectaries in the leaves, ovaries with
2 ovules in each locule, fruit that open explosively and seeds with no fleshy outgrowth (caruncle).
Phyllanthaceae has 54 to 60 genera with around 2000 to 2330 species including 16 from Australia. Work continues on the classification.
The following description only has the most commonly seen features and there are exceptions to most of them.
They are perennial trees, shrubs or occasionally climbers or annual herbs.
Deciduous or evergreen they have no latex in the bark or leaves and any hairs are simple.
Most have simple leaves on a petiole with a stipule at the base.
Leaves are almost always alternate in a spiral or 2 ranks (distichous).
They may occasionally be opposite, whorled or in clusters and a few are compound.
Blades have a smooth or sometimes toothed edge and may have simple hairs.
Inflorescences are mostly axillary with some terminal or above or below the axils.
They can be a single flower or a variously arranged spike-like or branched cluster or a dense head. There are small bracts.
The regularly shaped flowers are mostly unisexual with males and females on the same or different plants.
There are 4 to 6 (2 to 12) small sepals often with their bases fused.
There are often no petals but there may be 4 to 6 (same or less than the sepals) that are free. They are usually yellowish or green.
Male flowers have 3 to 10 (up to 50 or 60) stamens with their filaments free or fused into a tube.
The anthers mostly open inwards through longitudinal slits or sometimes apical pores.
There may be a rudimentary ovary (pistillode).
Female flowers have a superior ovary with 3 (2 to 5 or more) locules each with 2 ovules with axile placentation.
Frequently only one ovule in each locule develops into a seed.
The styles are usually basally fused and the stigmas vary.
There may be small infertile stamens (staminodes).
There is often a lobed or annular nectary disk that usually lies outside the stamens in male flowers or around the ovary in females.
Fruit are mostly a dry schizocarp and rarely a berry or drupe.
Schizocarps are septicidal capsules that split, sometimes explosively at the septae into mericarps each from one of the usually 3 carpels.
Each contains 1 or 2 three angled seeds.
The central column they were attached to, the columella, remains.
Phyllanthaceae is divided into 2 subfamilies (clades by some):
1. Phyllanthoideae (clusters of axillary flowers each attached separately to the node) divided into 4 tribes and