Streptothamnus F.Muell. — Redberry-vine

Treatment and Overview

Streptothamnus F.Muell., commonly called redberry-vine, is a monotypic genus of woody rainforest climbers in the Coralplant Family, Berberidopsidaceae. Its sole accepted species is Streptothamnus moorei F.Muell., the coast redberry-vine, native to eastern Australia from southeastern Queensland into northeastern New South Wales. It grows primarily in subtropical and warm-temperate rainforest and was established as a genus by Ferdinand von Mueller in 1862 (Royal Botanic Gardens, Kew 2026).

Mueller introduced Streptothamnus for the Australian S. moorei and tentatively associated a second species, S. beckleri, in 1862. Their geographic proximity obscured a deeper evolutionary difference. Veldkamp’s 1984 revision showed that the floral, pollen, seed, and wood-anatomical characters of S. beckleri aligned it with the Chilean genus Berberidopsis, and transferred it to Berberidopsis beckleri. The original epithet of the coast redberry-vine appeared as “moorii” in 1862 but was corrected to “moorei” in Mueller’s 1863 index; the corrected spelling is now standard. Anatomical and pollen studies supported the generic separation (Mueller 1862; Veldkamp 1984; van Heel 1984; Baas 1984).

Molecular evidence has now resolved the higher relationship. Menegoz et al. (2024) sampled all living Berberidopsidales with both nuclear and chloroplast markers and recovered coast redberry-vine as the sister lineage of a strongly monophyletic Berberidopsis. The crown of Berberidopsidaceae, representing the split between redberry-vine and coralplant, was estimated at approximately 45.8 million years, compared with about 9.8 million years for the crown of Berberidopsis. The dates have broad uncertainty, but the much greater relative depth of the split reinforces the morphological evidence for retaining Streptothamnus as a distinct genus.

Distinction from coralplant (Berberidopsis)

The molecular result accords remarkably well with morphology. Veldkamp’s revision identified a suite of floral characters separating coast redberry-vine from coralplants, and anatomical studies found additional differences despite substantial structural similarities between the genera. The comparison below summarizes the most useful genus-level distinctions (Veldkamp 1984; Baas 1984; van Heel 1984).

Character	**Streptothamnus moorei**	*Berberidopsis*
Floral organization	Cyclic, with distinct floral whorls	Predominantly acyclic or spiral
Perianth	Usually 5 persistent sepals + 5 deciduous petals	About 13-17 tepals grading from outer sepaloid to inner petaloid structures
Extrastaminal disk	Absent	Large, lobed, and persistent
Stamens	Numerous	Usually 6-13 in a single series
Filaments	Slender and longer than the anthers	Short and stout
Anthers	Straight and smooth	More or less curved and muriculate
Persistent structure beneath mature fruit	Calyx	Extrastaminal disk

Vegetative anatomy is more similar between the genera than their flowers suggest. Differences in indumentum, crystal complement, and epidermal morphology nevertheless independently support the floral distinctions summarized above (Baas 1984; Veldkamp 1984).

Horticultural and Agricultural Uses

Coast redberry-vine has not developed a significant horticultural or commercial role. Its pale pink to cream flowers were described by collectors as very fragrant, and its glossy foliage and dark reddish-black mature fruits give the plant ornamental interest. It remains primarily a rainforest species of specialist botanical interest; early collectors described it as rare but locally common in portions of its range (Veldkamp 1984; Royal Botanic Garden Sydney 2026).

Its native ecology provides the clearest guidance for any future cultivation. Coast redberry-vine occurs in humid eastern Australian rainforest and forest edges, so provenance from cool, moist, sheltered environments is more informative than treating it as horticulturally interchangeable with the Australian tape-vine coralplant merely because the two can occur in the same broad region.

Conservation Issues

Kew’s predictive extinction-risk model reports coast redberry-vine as “not threatened,” but this is a model-based estimate rather than a formal global IUCN assessment. The species remains restricted to the eastern Australian rainforest belt. Its extinction would eliminate both its monotypic genus and one of the two surviving generic branches of Berberidopsidaceae (Royal Botanic Gardens, Kew 2026; Menegoz et al. 2024).

Maintaining intact rainforest habitat across southeastern Queensland and northeastern New South Wales is therefore important not only for the species locally but also for preserving the deep evolutionary split represented by redberry-vine within the Coralplant Family.

Accepted Taxa

Accepted taxa of Streptothamnus

Streptothamnus moorei	F.Muell.	Coast redberry-vine

Additional Information

iNaturalist: Streptothamnus (opens in a new tab): Genus taxon page and observations.
Plants of the World Online: Streptothamnus (opens in a new tab): Accepted monotypic genus.
Plants of the World Online: Streptothamnus moorei (opens in a new tab): Taxonomy and extinction-risk prediction for the sole species.
PlantNET FloraOnline: Streptothamnus moorei (opens in a new tab): Regional Australian flora treatment with diagnostic characters and habitat.

References and Further Reading

Baas P (1984) Vegetative anatomy and taxonomy of Berberidopsis and Streptothamnus (Flacourtiaceae). Blumea 30(1): 39–44.

Menegoz K, Villarroel AE & Lavandero N (2024) Phylogeny of Berberidopsidales based on nuclear and chloroplast loci, with the description of a new species of Berberidopsis endemic to Central Chile. Taxon 73: 800–817. https://doi.org/10.1002/tax.13170 (opens in a new tab)

Mueller F von (1862) Fragmenta phytographiae Australiae 3: 27–28.

Royal Botanic Garden Sydney (2026) PlantNET - FloraOnline: Streptothamnus moorei F.Muell. Royal Botanic Garden Sydney. https://plantnet.rbgsyd.nsw.gov.au/cgi-bin/NSWfl.pl?lvl=sp&name=Streptothamnus~moorei&page=nswfl (opens in a new tab). Accessed 17 October 2026.

Royal Botanic Gardens, Kew (2026) Plants of the World Online: Streptothamnus F.Muell. Royal Botanic Gardens, Kew, Richmond, UK. https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:4398-1 (opens in a new tab). Accessed 17 October 2026.

Royal Botanic Gardens, Kew (2026) Plants of the World Online: Streptothamnus moorei F.Muell. Species profile and angiosperm extinction-risk prediction. Royal Botanic Gardens, Kew, Richmond, UK. https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:123038-3/general-information (opens in a new tab). Accessed 17 October 2026.

van Heel WA (1984) Flowers and fruits in Flacourtiaceae. V. The seed anatomy and pollen morphology of Berberidopsis and Streptothamnus. Blumea 30(1): 31–37.

Veldkamp JF (1984) Berberidopsis (Flacourtiaceae) in Australia. Blumea 30(1): 21–29. https://repository.naturalis.nl/document/565997 (opens in a new tab)