Centipeda minima subsp. minima
Common name
sneezeweed, centipeda
Synonyms
Myriogyne minuta (G.Forst.) Less., Cotula minuta G.Forst, Centipeda orbicularis Lour.,
Family
Asteraceae
Flora category
Vascular – Native
Endemic taxon
No
Endemic genus
No
Endemic family
No
Structural class
Herbs - Dicotyledonous composites
Chromosome number
2n = 20
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 | Threatened – Nationally Endangered | Qualifiers: EF, SO
Previous conservation statuses
2009 | Threatened – Nationally Critical | Qualifiers: SO, EF
2004 | Threatened – Nationally Critical
Distribution
Indigenous. New Zealand: Kermadecs (Raoul Island), and North Island. The majority of historic records unsupported by herbarium specimens have to be regarded as unreliable due to confusion with three other species recently recognised in New Zealand, the endemic C. aotearoana, and indigenous C. cunninghamii and C. elatinoides. Recent confirmed records of C. minima have come recently from Raoul Island (May 2011) and from the North Island, from about the Waikato and Bay of Plenty north. Present also in Australia, India, Russia, China, Japan, Malesia and on some Pacific Islands.
Habitat
Wet, or partially dried out lake, pond and stream margins. Often in coastal areas. This species requires open sparsely vegetated ground It cannot tolerate any competition, so grows in the most open sites it can find (wet or dry). The largest recently discovered populations in New Zealand come from rubbish dumps, poorly draining foot paths, and muddy ground associated with poorly drained airstrips.
Features
Aromatic, usually prostrate, annual, bright green, spreading herb up to 250 mm diam and 200 mm high. Branches numerous, spreading, frequently rooting from lower leaf nodes, glabrescent or finely covered in cottony, wispy hairs. Leaves spathulate, rhomboidal 3-27 mm x 1.5-11 mm, light green to dark green, never glaucescent, usually glabrescent sometimes cottony hairy, lamina margin serrated with 1-4 pairs of teeth, these usually confined to the upper third of lamina. Inflorescence a solitary, sessile to subsessile, axillary , leaf opposed capitulum. Capitula hemispherical to subglobular, 1.5-5 mm diam., greenish-yellow; involucral bracts obovate, 1-1.6 mm, receptacle convex; corolla of female flowers 0.1-0.25 mm, bisexual florets 0.3-0.4 mm. Fruiting heads disarticulating at maturity. Cypselas narrowly obcuneate, 0.6-1.5 mm, truncate or obtuse, with 4-8 ribs bearing short antrorse bristles, uniting as a pale, pithy apical cap in distal quarter.
Similar taxa
The three other indigenous species Centipeda aotearoana, C. cunninghamii, and C. elatinoides are much larger usually perennial plants. From these C. minima subsp. minima is distinguished by its small size, usually annual habit, bright green, kite-shaped leaves that are < 10 mm long and usually less than 3 x times as wide, and which are only sparingly (though deeply) toothed toward the leaf apex.
Flowering
(August-) December (-May)
Flower colours
Green, Yellow
Fruiting
(August-) December (-May)
Life cycle
Cypselae dispersed by wind, attachment and granivory (Thorsen et al., 2009).
Propagation technique
A strict annual that is easily grown from fresh seed and rooted pieces. Once established it regularly self-sows in suitable habitats and can at times become invasive. It makes an ideal semi-permanent ground cover, for poorly draining lawns, where in ideal conditions the plants rapid growth and frequent turn over can provide an excellent, pleasantly fragrant alternative to lawn grasses, without the need for mowing. For a more permanent cover try mixing it in with Cotula (Leptinella spp.).
Threats
The major threats come from aggressive wetland weeds, such as Mercer grass (Paspalum distichum), which rapidly smothers the open muddy ground this species favours. This species is weedy and opportunistic and so can potentially be found anywhere there is suitably open, muddy, ground.
Etymology
centipeda: From the Greek word for one hundred feet
minima: Very small
Attribution
Fact sheet prepared for NZPCN by P.J. de Lange 5 May 2005. Description adapted from Walsh (2001).
References and further reading
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
Walsh, N. G. 2001: A revision of Centipeda (Asteraceae). Muelleria 15: 33-64.
Citation
Please cite as: de Lange, P.J. (Year at time of access): Centipeda minima subsp. minima Fact Sheet (content continuously updated). New Zealand Plant Conservation Network. https://www.nzpcn.org.nz/flora/species/centipeda-minima-subsp-minima/ (Date website was queried)