Browallia americana

Browallia americana.

The rarely seen species is naturalised in some areas of Australia.
Bush violets are markedly variable plants.
They are small annual sparsely branched plants around 30 (60) cm high.
The erect or straggling stems may be woody at the base.
The green and purple branches have simple hairs with or without glands.

The ovate to elliptic leaves are on a petiole up to 2 cm long that often has wings.
The blade is up to around 5 cm long and 3 cm wide.
The tip is pointed and the base heart- or wedge-shaped.
There are simple and glandular hairs on the veins on the lower surface and a there may be a few on the upper.

Axillary inflorescences are a solitary flower or a small cluster.
The erect flowers are on a pedicel around 4 mm long that lengthens in the fruit.
The pedicel usually has simple and glandular hairs.

The angled calyx tube, up to 1 cm long has unequal lobes up to around 3.5 mm long.
There may be dense glandular hairs on the outer surface.

The corolla tube, up to 1.5 or 2 cm long is swollen near the top then constricts to a 2 mm wide throat.
The 4 (5) spreading lobes, up to 8 mm long curve back and may be notched (bi-lobed).
Flowers sometimes look as if they have 2 lips.
There are hairs on the outer surface of the tube and lobes.
The deep blue flowers have a white or pale yellow throat.

The 4 stamens are in 2 pairs of different lengths.
The short upper pair have 2 mm long filaments with dense hairs.
The lower pair, with 3.5 mm filaments only have a few hairs.
The ovary, up to 6 mm long has a few simple hairs on the top.
The style, around 12 mm long has a bi-lobed stigma that sits between the anthers.

The capsules, around 5 mm long are surrounded by the calyx.
They open, from the top into 4 sections or valves releasing the numerous tiny seeds.

There are a few more bushy cultivars with different flower sizes and shades of blue and one with white flowers.