Hypericum pusillum
Common names
swamp hypericum
Biostatus
Native
Category
Vascular
Structural class
Herbs - Dicotyledons other than Composites
Flower colours
Yellow
Detailed description
Perennial or annual, non-rhizomatous herbs. Stems usually up to 200 mm long, 0.3–0.6 mm diameter, usually prostrate to decumbent, sometimes erect, often with adventitious roots at base, without marginal pellucid glands, quadrangular, usually branched below inflorescence. Leaves sessile, 2.5–9.0 × 1.5–3.5 mm, usually broadly elliptic to elliptic, often strongly sinuate, light green to yellow-green, undersides slightly paler; pellucid glands up to 0.1 mm diameter, translucent in light, >25 glands conspicuous on upper 2/3 of leaf underside, inconspicuous on upper leaf surface; base attenuate; margin usually sinuate; apex subacute to obtuse; main lateral veins 1 to 2, basal, tertiary reticulation not visible. Inflorescence terminal, flowers solitary. Pedicels 3.7–3.8 × 0.3–0.4 mm, green, quadrangular. Flower up to 9 mm diameter; bud cylindric ellipsoid, apex subacute. Sepals 5, 2.8–4.7 × 0.9–1.4 mm, unequal, free, spreading, oblong, narrow elliptic, or elliptic-oblong, sometimes sinuate, green; margin translucent, glands absent; base free, attenuate; apex subacute to rounded, sometimes with a small apiculus. Petals 5, 2.8–4.0 × 1.7–2.5 mm, pale yellow to dark yellow, obovate to oblong; glands absent; margins entire. Stamens 9, free, c.2.1 × 0.1 mm diameter, translucent, pale yellow, slightly curved, terete; anthers 0.2–0.3 mm long, yellow. Ovary c.1.3 × 1.0–1.1 mm, ovoid, weakly trigonous in cross section, light green; styles 3-4, 0.3–0.5 mm long, spreading, translucent; stigma c.0.2 mm diameter. Capsule 2.8–4.5 × 2.2–3.8 mm, cylindric to globose, shorter or longer than sepals. Seeds 0.50–0.75 × c. 0.30 mm, testa orange-brown to light yellow, aging to dark brown, oblong to elliptic-oblong, terete, semi-glossy, finely reticulate, longitudinal ribs absent
Similar taxa
Most often confused with the introduced Hypericum humifusum and indigenous H. involutum. From H. humifusum, with which it often grows it is easily distinguished by its usually smaller size, leaves with typical undulating margins, which lack the conspicuous band of black glands diagnostic of H. humifusum. From H. involutum, H. pusillum differs by its prostrate rather than erect stems, usually undulate rather than revolute leaf margins, and smaller flowers (5-9 mm cf. 18-16 mm diameter).
Distribution
Indigenous. New Zealand: North, South and Stewart Islands. Also Australia, New Guinea, Malesia, SE Asia, Chian and Japan.
Habitat
Coastal to subalpine, on river and stream banks, lake and tarn margins, swamps and bogs, open areas in forest, and damp hollows among tussocks and within cattle-pugged, poorly drained pasture.
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
Australasian plants have long been known (incorrectly) as Hypericum japonicum Thunb.
Endemic taxon
No
Endemic genus
No
Endemic family
No
Ecology
Flowering
Throughout the year
Fruiting
Throughout the year
Life cycle and dispersal
Seeds are wind and water dispersed (Thorsen et al., 2009).
Propagation technique
Easily grown from fresh seed and rooted pieces. An attractive ground cover for poorly drained clay soils.
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]
OBL: Obligate Wetland
Almost always is a hydrophyte, rarely in uplands (non-wetlands).
Other information
Etymology
hypericum: From the Greek hyper (above) and eikon (picture), the plant was hung above pictures to ward off evil spirits
pusillum: Insignificant, weak
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.
HYPPUS
Chromosome number
2n = 16
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 Not Threatened
Referencing and citations
References and further reading
Heenan, P.B. 2008: Three newly recognised species of Hypericum (Clusiaceae) from New Zealand. New Zealand Journal of Botany 46: 547-558.
Thorsen, M.J.; Dickinson, K.J.M.; Seddon, P.J. 2009: Seed dispersal systems in the New Zealand flora. Perspectives in Plant Ecology, Evolution and Systematics 11: 285-309.
Attribution
Fact Sheet prepared for the NZPCN by P.J. de Lange (17 April 2011). Description from Heenan (2008).
NZPCN Fact Sheet citation
Please cite as: de Lange, P.J. (Year at time of access): Hypericum pusillum Fact Sheet (content continuously updated). New Zealand Plant Conservation Network. https://www.nzpcn.org.nz/flora/species/hypericum-pusillum/ (Date website was queried)