Guinea Flowers are sometimes cultivated for their bright yellow flowers.
There are about 145 species with around 110 being endemic to Australia.
Most are small to medium shrubs and some are prostrate.
A few species climb by twining their stems around supports.
Height varies from 20 cm to 2 to 5 m and the prostrate forms can be 2 m wide.
Stems are much branched and may be reddish especially when young.
The stems of some root at the nodes.
Young leaves and twigs may be covered in soft hairs.
The simple leaves are alternately arranged with a short or no stalk.
Leaf size ranges from 4 mm long x 3 mm wide up to 10 cm long by 3 cm wide.
They can be linear, elliptic, ovate, oblong or lanceolate.
The tip can be sharp or blunt.
They are mostly a glossy dark green but may be purplish or bronzed.
The margins are mostly smooth but a few have scattered or coarse teeth.
The blade can be flat but the edges are often rolled under.
The upper and/or lower surface can be smooth or covered in silky or stiff hairs.
The flowers are mostly terminal and solitary.
Each flower is short lived but they flower over a long period.
They may or may not have a stalk and there are bracts around them.
Flower size varies from 1.2 cm up to 4 or 5 cm across.
There are 5 persistent sepals whose outer surface can be smooth or densely hairy.
The 5 (or less) petals are mostly a bright yellow but there are a few species with orange or white.
The petals fall off early.
They are round or ovate with tips that may be shallowly notched or bilobed.
Characteristically there are many stamens surrounding the carpels.
Some species have only a few stamens and some may be infertile staminodes.
Stamens can be free or have their bases joined.
They can be in a single group on one side of the carpels or in up to 16 bundles.
There are 2 to 5 carpels in the superior ovary each with a style that is often curved.
Each carpel can have 1 to many ovules.
The fruit are dehiscent follicles with the sepal remnants attached.
They dehisce at the apex.