Solanum americanum
Common names
small-flowered nightshade
Biostatus
Native
Category
Vascular
Structural class
Herbs - Dicotyledons other than Composites
Flower colours
Violet/Purple, White
Detailed description
Small, annual to perennial bright-green to purple-green herb up to 1 x 1 m but usually much less. All parts glabrous to glabrescent except on occasion on very young growth. Branches and branchlets usually unarmed though sometimes furnished on the flanges with sparse blunt-ended hooks. Petioles to 50 mm long. Cauline leaves 40-100 x 15-55 mm, usually bright green rarelt dark green, ovate, ovate-oblong to lanceolate-ovate, entire or distally coarsely toothed to lobulate, sometimes sinuate; base cuneate, broad-cuneate or attentuate, rarely cordate to truncate; apex more or less acute, sometimes acumininate. Flowers in few-flowered umbels. Peduncles 20 mm long, slender; pedicels up to 5 mm long, more or less pendent, markedly deflexing at fruiting. Calyx <2 mm long, accrescent; lobes very narrowly elliptic to ovate, reflexed at fruiting. Corolla 5-8 mm diameter, stellate, white, pale mauve, glabrous; lobes triangular. Anthers 1.0-1.5 mm long, yellow. Fruit a berry 5-8 mm diameter, globular, glossy black to purple-black, stone cells present, often copious. Seeds 1.0-2.5 mm long, semi-glossy buff to pale orange-yellow or dark yellow, obovate to broadly obovate, sometimes circular, asymmetric, strongly compressed.
Similar taxa
Most frequently confused with Solanum nigrum, with which it often grows on the more disturbed northern offshore islands. From S. nigrum, S. americanum differs by its umbellate rather than pseudoumbellate inflorescences, smaller flowers (5-8 cf 8-13 mm diameter), strongly reflexed, narrow calyx lobes in fruiting specimens, smaller anthers (1-1.6 cf. 2-2.7 mm long), and by the presence of stone cells, these being absent in S. nigrum. Both species are chromosomally distinct, with S. nigrum having 2n = 72 and S. nodiflorum 2n = 24 chromosomes. Solanum americanum is indeed the correct name for the New Zealand plant (S. Knapp pers. comm., July 2017) that has been recently (Manoko et al. 2007) though incorrectly, referred back to S. nodiflorum (as S. nodiflorum subsp. nutans). The treatment offered here is for this species (there as S. americanum) by Webb et al. (1988) is correct. A third species, S. opacum, is also present in New Zealand, and that species has caused much confusion between S. americanum and S. nigrum because it has deflexed, broad calyx-lobes, dull black- or green-coloured fruits with stone cells, and stamens which are 1.5 mm long - features that are ‘intermediate’ between S. americanum and S. nigrum as treated by Webb et al. (1988). However, Webb et al. (1988) state that S. opacum is not present in New Zealand, which is now known to be incorrect. For differences between S. americanum and S. opacum see the factsheet for S. opacum.
Distribution
Indigenous. Kermadec, Three Kings, North, South and Chatham Islands. In the North Island locally common to about the Bay of Plenty and Taranaki; scarce otherwise. In the South Island reported from Nelson, Marlborough, North Canterbury and Westland. Uncommon on the Chatham Islands. Abundant on northern offshore islands, especially the Kermadec Islands.
Present also in Australia, Africa, India, south-east Asia and the Pacific.
Habitat
Usually coastal but also found inland in open forested situations up to about 400 m a.s.l. Occasionally an urban weed.
Solanum americanum is the typical Solanum of northern offshore islands, where it grows in great abundance on the richly manured, frequently disturbed ground of petrel colonies, and may on occasion form dense thickets.
Current conservation status
The conservation status of all known New Zealand vascular plant taxa at the rank of species and below were reassessed in 2022-2023 using the New Zealand Threat Classification System (NZTCS) – more information about this can be found on the NZTCS website. This report includes replaces all previous NZTCS lists for vascular plants. Previous assessments can be found here.
- Conservation status of vascular plants in Aotearoa New Zealand, 2023. 2024. Peter J. de Lange, Jane Gosden, Shannel P. Courtney, Alexander J. Fergus, John W. Barkla, Sarah M. Beadel, Paul D. Champion, Rowan Hindmarsh-Walls, Troy Makan and Pascale Michel Department of Conservation. Source: NZTCS and licensed by DOC for reuse under the Creative Commons Attribution 4.0 International licence.
2023 | Not Threatened | Qualifiers: SO
Detailed taxonomy
Family
Synonyms
Solanum nodiflorum Jacq.; Solanum nodiflorum subsp. nutans R.J.F.Hend.; S. americanum subsp. nutans (R.J.F.Hend.) R.J.F.Hend.
Endemic taxon
No
Endemic genus
No
Endemic family
No
Ecology
Flowering
October - April
Fruiting
November - June
Propagation technique
Very weedy and invasive
Wetland plant indicator status rating
Information derived from the revised national wetland plant list prepared to assist councils in delineating and monitoring wetlands (Clarkson et al., 2021 Manaaki Whenua – Landcare Research Contract Report LC3975 for Hawke’s Bay Regional Council). The national plant list categorises plants by the extent to which they are found in wetlands and not ‘drylands’. The indicator status ratings are OBL (obligate wetland), FACW (facultative wetland), FAC (facultative), FACU (facultative upland), and UPL (obligate upland). If you have suggestions for the Wetland Indicator Status Rating, please contact: [Enable JavaScript to view protected content]
FACU: Facultative Upland
Occasionally is a hydrophyte but usually occurs in uplands (non-wetlands).
Other information
Etymology
solanum: Derivation uncertain - possibly from the Latin word sol, meaning “sun,” referring to its status as a plant of the sun. Another possibility is that the root was solare, meaning “to soothe,” or solamen, meaning “a comfort,” which would refer to the soothing effects of the plant upon ingestion.
NVS code
The National Vegetation Survey (NVS) Databank is a physical archive and electronic databank containing records of over 94,000 vegetation survey plots - including data from over 19,000 permanent plots. NVS maintains a standard set of species code abbreviations that correspond to standard scientific plant names from the Ngä Tipu o Aotearoa - New Zealand Plants database.
SOLAME
Chromosome number
2n = 24
Previous conservation statuses
The conservation status of all known New Zealand vascular plant taxa at the rank of species and below were reassessed in 2022-2023 using the New Zealand Threat Classification System (NZTCS) – more information about this can be found on the NZTCS website. This report includes replaces all previous NZTCS lists for vascular plants. Previous assessments can be found here.
- Conservation status of vascular plants in Aotearoa New Zealand, 2023. 2024. Peter J. de Lange, Jane Gosden, Shannel P. Courtney, Alexander J. Fergus, John W. Barkla, Sarah M. Beadel, Paul D. Champion, Rowan Hindmarsh-Walls, Troy Makan and Pascale Michel Department of Conservation. Source: NZTCS and licensed by DOC for reuse under the Creative Commons Attribution 4.0 International licence.
2017 | Not Threatened | Qualifiers: SO
2012 | Not Threatened
2009 | Not Threatened
2004 | Not Threatened
Regional conservation statuses
The regional threat classification system leverages off the national assessments in the NZTCS, providing information relevant for the regional context. Otago conservation status information is sourced from the “Regional conservation status of indigenous vascular plants in Otago” Jarvie S et al. (2024) report.
Otago: 2024 | Regionally Data Deficient
Referencing and citations
References and further reading
Allan, H.H. 1961: Flora of New Zealand. Vol. I. Government Printer, Wellington.
Manoko, M.L.K.; van den Berg, R.G.; Feron, R.M.C.; van der Weerden, G.M.; Mariani, C. 2007: AFLP markers support separation of Solanum nodiflorum from Solanum americanum sensu stricto (Solanaceae). Plant Systematics and Evolution 267: 1-11.
Webb C.J., Sykes W.R., Garnock-Jones P.J. 1988: Flora of New Zealand. Vol. IV. Botany Division, DSIR, Christchurch.
Attribution
Fact Sheet prepared for the NZPCN by P.J. de Lange (12 May 2006). Description by P.J. de Lange with some elements based on Allan (1961) and Webb et al. (1988).
Some of this factsheet information is derived from Flora of New Zealand Online and is used under a Creative Commons Attribution 3.0 New Zealand licence.
NZPCN Fact Sheet citation
Please cite as: de Lange, P.J. (Year at time of access): Solanum americanum Fact Sheet (content continuously updated). New Zealand Plant Conservation Network. https://www.nzpcn.org.nz/flora/species/solanum-americanum/ (Date website was queried)