Leptinella rotundata
Synonyms
Cotula dioica var. rotundata Cheeseman, Cotula rotundata (Cheeseman) D.G.Lloyd
Family
Asteraceae
Flora category
Vascular – Native
Endemic taxon
Yes
Endemic genus
No
Endemic family
No
Structural class
Herbs - Dicotyledonous composites
Chromosome number
2n = c.312
Current conservation status
The threat classification 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) – more information about this can be found on the NZTCS website 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. Please note, threat classifications are often suggested by authors when publications fall between NZTCS assessment periods – a suggested threat classification status has not been assessed by the NZTCS panel.
Source: NZTCS and licensed by DOC for reuse under the Creative Commons Attribution 4.0 International licence.
2018 | Threatened – Nationally Endangered
Previous conservation statuses
2017 | Threatened – Nationally Endangered | Qualifiers: DP, RR, Sp, St
2012 | Threatened – Nationally Vulnerable | Qualifiers: St
2009 | Threatened – Nationally Critical | Qualifiers: DP, Sp
2004 | Threatened – Nationally Vulnerable
Distribution
Endemic. North Island. Known only from the west coast from the Waitakere Ranges to Scott’s Point, Te Paki.
This species should be looked for in any suitable cliffside habitat along the west coast of the northern North Island. In some respects it has a distribution similar to another west coast endemic Hebe speciosa, which has been recorded at three of the five known sites for L. rotundata. The species was rediscovered in the Waitakere Ranges in April 2010 some 113 years after it was first found there by Thomas Cheeseman and 104 years after it was described by him as new to science from those gatherings.
Habitat
Coastal cliff faces and boulder falls. Occupies a very specific habitat, i.e. preferring the wind and salt-blasted margins of vegetated cliff faces, where other competing plants are held in check. Typically sparse and patchy in its distribution at any given site.
Features
Creeping perennial herb forming diffuse patches. Rhizomes on soil surface, dark green or purple-green, sparsely covered in long, silky hairs. Branches few, occurring at flowering nodes. Leaves paired, spaced 10-30 mm apart. Short shoots alternating on both sides of rhizome, these with 3-4 leaves. Leaves simple 10-50 x 5-15 mm, suborbicular, membranous, yellow-green, sometimes purple-brown pigmented toward leaf base, both surfaces sparsely covered in long silky hairs, veins not evident. Leaf margins crenate. Flowers monoecious, yellow-green, arising directly from rhizomes on stout, villous peduncles 20-60 mm long. Heads of capitula 5-7 mm diam., hemispherical, with 6-12 phyllaries (bracts) in 1-2 subequal rows, broadly elliptic, green, villous, with a distinct, sometimes finely toothed brown pigmented margin. Pistillate (female) florets usually 0-5, sometimes up to 12 in 1 incomplete row, staminate (male) flowers 40-90. Achenes (seeds) 1.9 x 1.1 mm, brown.
Similar taxa
Easily distinguished from other Leptinella species by the suborbicular leaves and high chromosome number. Lloyd (1972) indicates that the reproductive system, coupled with the high chromosome number and northern distribution, are unusual traits in Section Elongata, within which this species belongs, and infers from that that L. rotundata is potentially a relic species within this section.
Flowering
August to January (but sporadic flowering can occur at any time of the year)
Flower colours
Brown, Green
Fruiting
October to April (but fruiting material can be found at any time of the year)
Life cycle
Papery cypselae are dispersed by wind and possibly attachment (Thorsen et al., 2009).
Propagation technique
Very easily grown by division of established plants. In the wild female plants occur in isolation from “males” so seed set is minimal, and restriction to hermaphroditic flowers on “male” plants. For this reason most plants in cultivation are raised from division of larger individuals. In cultivation this species is often short-lived and benefits from regular division to keep plants vigorous.
Threats
This species is threatened at all known locations by coastal erosion, weed invasion of its narrow cliff-top and boulder bank habitats, and by the seemingly natural separation of male and female plants. Thus in the wild, as far as is known, seed is rarely if ever formed. The separation of the sexes is not unique to this species in the genus, being also the case for Leptinella dispersa subsp. rupestris (D.G.Lloyd) D.G.Lloyd et C.Webb.
Etymology
leptinella: From the Greek word leptos (meaning slender, thin or delicate), referring to the ovary
Attribution
Fact sheet prepared for NZPCN by P.J. de Lange (31 August 2006). Description from Lloyd (1972) - as Cotula rotundata.
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.
NZPCN Fact Sheet citation
Please cite as: de Lange, P.J. (Year at time of access): Leptinella rotundata Fact Sheet (content continuously updated). New Zealand Plant Conservation Network. https://www.nzpcn.org.nz/flora/species/leptinella-rotundata/ (Date website was queried)