Light Blue Snakeweed.
It is possibly the same species as Stachytarpheta indica.
From Central America and the Caribbean area it is naturalised in S.E. Queensland.
They are shrubs 1 to 2 m high.
The young stems are 4-angled and only have a few hairs.
The opposite leaves, up to 10 cm long, have shallow teeth on the edge apart from the base.
There may be a few hairs or none at all.
The terminal inflorescences are narrow, erect, curved spikes up to 50 cm long.
There are bracts with pointed tips at the base of the stalkless flowers.
The calyx tube is around 6 mm long with 5 lobes only 1 mm long.
The curved corolla tube is around 10 mm long with 5 lobes 2 – 3 mm long.
The lobes are unequal with the upper 2 being larger.
There are glandular hairs in the throat and down the tube.
Flowers are pale blue with some mauve or almost white.
There is a white area on the base of the upper 2 lobes.
There are 2 stamens and 2 staminodes.
The fruit are shiny dark schizocarps that split into 2 halves (mericarps).
Each mericarp has 1 seed each.