Lobelia purpurascens

Lobelia purpurascens.

Native to Australia it can be a weed.
They are perennial prostrate, scrambling or erect herbs.
The white underground stems (rhizomes) give the plant its common name of White Root.
Smooth purple above ground stems can be over 30 cm long.
They may be zigzagged and can root at the nodes.

Alternately arranged leaves may have a petiole up to 2 mms long but frequently have none.
Blades, up to 3 cm long and 1.5 cm wide can be ovate, elliptic or lance-shaped.
The tip is rounded, the edge toothed and the lower surface is usually purplish.
There are usually very small hairs on the upper surface.

Axillary inflorescences are a solitary flower on a stalk (pedicel) up to 6 or 7 cm long.
The bases of the sepals are fused into a short tube with 5 spreading lobes.
Lobes are around 2 or 3 mm long with at least 1 pair of teeth near the base.

The resupinate (upside down) flowers have a corolla tube up to 1 cm long with 5 lobes.
The two narrow pointed lobes in the upper lip are erect, around 4 mm long and up to 1 mm wide.
The 3 more spreading lower lobes are up to around 5 mm long and 2 to 3 mm wide with a rounded tip.
The tube is slit almost to the base on the upper side and there are small hairs in the throat.
Petals are white but often with a pink, blue or purplish tinge mainly on the outer surface.

Flowers are unisexual with male and female on different plants.
Male flowers have 5 stamens with filaments 4 to 5 mm long.
Only some of the fused anthers, around 1.5 mm long have any apical bristles.
The ovary is rudimentary.
Female flowers have much smaller stamens with sterile anthers.
The inferior ovary, around 3 mm long has numerous ovules in the 2 locules.
The roughly spherical capsules, up to 1 cm long have brown pitted seeds.