Pygmy button daisy
Cotula nana D.G.Lloyd
Vascular – Native
Herbs - Dicotyledonous composites
2n = 52
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 Critical | Qualifiers: CD, EF, Sp
Previous conservation statuses
2009 | Threatened – Nationally Endangered | Qualifiers: CD, EF, Sp
2004 | Threatened – Nationally Endangered
Endemic. North and South Islands. In the North Island it is only known from the south western coastline at one site near Titahi Bay. In the South Island it is known from two sites, one at the Rai Valley, Marlborough and the other near Mount Pleasant, in the Port Hills, near Christchurch, Canterbury.
The habitat of L. nana varies from forest to coastal and montane cliff-top grassland, but common features are the need for disturbance patches, shelter, and supply of moisture. The species appears to have adopted a strategy of constant colonisation of small patches of bare ground and so occupies a highly dynamic and changing micro-habitat.
Diminutive, much-branched, monoecious, perennial herb forming small, diffuse patches. Rhizomes at soil surface, slender, 0.5 mm diam., green, sparsely pilose hairy. Leaves 1-several at apex, mostly distant. Leaves 1-pinnatifid, 4-20 x 0.2-0.4 mm; blade 0.3-15 mm, obovate to narrow-obovate, membranous, green usually without brown pigmentation, glabrous or sparsely pilose hairy, pinnae 6-10 pairs,distal ones close-set or overlapping, proximal ones distant; teeth 0-3 on distal margins of proximal pinnae. Peduncles shorter than leaves, 0.3-10 mm, glabrous to pilose. Capitula 1-2 mm diam, yellow, surface convex, involucre hemispherical; phyllaries 20 in 2 subequal rows, oblong or obovate, red-green, villous, with wide, brown-tipped, scarious margins. Pistillate florets 20-30, staminate 5-7 both in 2 rows, c.1 mm long, straight, yellow-green; corolla equal in length and width. Achenes 1 x 0.5 mm, ovoid, green-brown.
Easily distinguished from all other indigenous, small-leaved, diminutive Leptinella species by the branches which radiate from a central cluster, rhizome leaves crowded at the apex, short shoots absent or reduced, leaf bases, phyllaries and florets which lack dark veins; and by the slender rhizomes up to 0.5 mm diam, membranous leaves, and yellow-green capitula up to 2 mm diam.
Early Spring to end of October and early autumn to early winter
Through out the year
Papery cypselae are dispersed by wind and possibly attachment (Thorsen et al., 2009).
Easy from rooted pieces and often self sows and establishes in gardens. As it is very small it is easily lost by being over topped by taller plants. Does best in permanently open ground. An ideal plant, once established for high impact areas, though it seems to prefer a damp soil to do best.
Likely factors in any local extirpation of L. nana include loss of temporary open sites for colonisation, increased competition from other plants, opening up of protective vegetation allowing sites to dry out or become weedy, increased erosion or deposition of debris, excessive trampling by people and animals, loss of seed dispersal vectors like terrestrial birds and other animals, seed loss to unsuitable habitat, and indiscriminate herbicide use. Slugs are a threat to cultivated L. nana.
leptinella: From the Greek word leptos (meaning slender, thin or delicate), referring to the ovary
Fact sheet prepared for NZPCN by P.J. de Lange 31 August 2006. Description from Lloyd (1972) - as Cotula nana.
References and further reading
Lloyd, D.G. 1972: A revision of the New Zealand, Subantarctic, and South American species of Cotula, section Leptinella. New Zealand Journal of Botany 10: 277-372
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
Please cite as: de Lange, P.J. (Year at time of access): Leptinella nana Fact Sheet (content continuously updated). New Zealand Plant Conservation Network. https://www.nzpcn.org.nz/flora/species/leptinella-nana/ (Date website was queried)