Hypericum pusillum
Common name
swamp hypericum
Synonyms
Australasian plants have long been known (incorrectly) as Hypericum japonicum Thunb.
Family
Hypericaceae
Flora category
Vascular – Native
Endemic taxon
No
Endemic genus
No
Endemic family
No
Structural class
Herbs - Dicotyledons other than Composites
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.
HYPJAP
Chromosome number
2n = 16
Current conservation status
The conservation status of all known New Zealand vascular plant taxa at the rank of species and below were reassessed in 2017 using the New Zealand Threat Classification System (NZTCS). This report includes a statistical summary and brief notes on changes since 2012 and replaces all previous NZTCS lists for vascular plants. Authors: By Peter J. de Lange, Jeremy R. Rolfe, John W. Barkla, Shannel P. Courtney, Paul D. Champion, Leon R. Perrie, Sarah M. Beadel, Kerry A. Ford, Ilse Breitwieser, Ines Schönberger, Rowan Hindmarsh-Walls, Peter B. Heenan and Kate Ladley.
2012 | Not Threatened
Previous conservation statuses
2009 | Not Threatened
2004 | Not Threatened
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.
Features
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)
Flowering
Throughout the year
Flower colours
Yellow
Fruiting
Throughout the year
Life cycle
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.
Etymology
hypericum: From the Greek hyper (above) and eikon (picture), the plant was hung above pictures to ward off evil spirits
pusillum: Insignificant, weak
Attribution
Fact Sheet prepared for the NZPCN by P.J. de Lange (17 April 2011). Description from Heenan (2008).
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
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)