Bixaceae.
The achiote family has 3 genera with 25 species or as seen in Australia 4 genera with around 21 species.
The 3 genera are Bixa, Cochlospermum and Diegodendron.
According to Kew the genus Amoreuxia is now a synonym for Cochlospermum.
Plants are small trees, shrubs or herbs with rhizomes (underground stems).
They may be evergreen or loose their leaves in summer.
Parts may have simple hairs or peltate scales (scales on a stalk attached near the centre of the lower surface).
A red, orange or yellow sap or latex is secreted from damaged parts.
Leaves, on a petiole are alternately arranged in a spiral.
Stipules at the petiole base are of various types and fall early.
Blades are mostly simple and undivided but occasionally are palmately lobed.
Palmately lobed blades may have shallow to deeply dissected edges.
Typical undivided blades are ovate, lance-shaped, obovate or oblanceolate.
They have a prominent midrib and a heart-shaped base.
Edges can be smooth or have blunt or sharp teeth.
There are dots from oil glands.
The mainly terminal inflorescences are a spike or a branched cluster (panicle).
Each branch is a raceme with flowers on a pedicel, along a midrib.
The bottom flower on each branch opens first.
There are bracts in the inflorescences.
The 5 free sepals in the calyx alternate with the 5 free petals.
The yellow or pink petals have a rounded end that may have a notch.
The notch can be shallow or deep making the petals bi-lobed.
The numerous free stamens may be of the same or different lengths.
They may be in 5 or 10 bundles.
The basifixed anthers open inwards through apical pores or short slits.
The stamens can insert onto the nectiferous disc or between its lobes.
The superior ovary of 2 to 5 fused carpels has 2 to 5 locules with many ovules.
The placentation is axile or parietal or a mix of both.
The difference depends on how deeply the partitions go.
The single stlye has a spherical stigma.
The fruit are a loculicidal capsule with the other flower parts attached for a while.
They are covered in straight hairs.
The brown, yellow or white seeds may have matted hairs.
J.F.
