Plants of
South Australia
Dipteracanthus australasicus ssp. glabratus
Smooth Petunia
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Regional Species Conservation Assessments per IBRA subregion.
Least concern
Near threatened
Critically endangered
Data deficient
Coober Pedy
Mount Gambier
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Common names

Smooth Petunia


Dipteracanthus from the Greek 'di' meaning two, 'pteron' meaning wing and 'acantha' meaning thorn; referring to the two large leafy bracteoles enclosing the base of the corolla tube. Australasicus means of or from Australasian; referring to the species distribution. Glabratus from Latin meaning somewhat smooth; referring to the subspecies glabrous corolla throat, style and calyx.

Distribution and status

Endemic to South Australia and found in the far north-eastern corner, growing on creek bed, gibber plain and skeletal soil. Native. Rare in South Australia.
Herbarium region: Lake Eyre
AVH map: SA distribution map (external link)

Plant description

Perennial, more or less glabrous woody shrub to 80 cm tall. Leaf blade ovate to oblong, to 16.5 mm long and 11 mm wide, more or less glabrous, or a few short, white, recurved hairs on nodes, petioles and margins of leaves. Inflorescence either single per axil or triad appearing as a single flower. Flowers tubular corolla blue, corolla throat externally glabrous, internally glabrous or sometimes with a single row of hairs, style glabrous, calyx externally glabrous. This subspecies is easily distinguished from the three other subspecies of D. australasicus by its glabrous corolla throat, style and calyx. Flowering between August and October. Fruits are pale brow capsule to 14.5 mm long, with 6-8 seeds in 2 rows in each valve. Seed embryo type is bent.

Seed collection and propagation

Collect seeds between October and December. Collect capsules that are maturing, drying off and turning brown. Green capsules can be collected if the seeds are hard and brown. Place the capsules in a paper bag or tray and allow to dry for 1 to 2 weeks. Gently rub the dried capsule by hand or with a rubber bung to dislodge the seeds. Use a sieve to separate the unwanted material. Store the seeds with a desiccant such as dried silica beads or dry rice, in an air tight container in a cool and dry place.