Caltha obtusa
Common names
White caltha
Biostatus
Native – Endemic taxon
Category
Vascular
Structural class
Herbs - Dicotyledons other than Composites
Flower colours
White, Yellow
Detailed description
Glabrous rhizomatous perennial herb of alpine flushes, seepages, bogs and stream sides. Plants forming a compact turf, when flowering with scapes 20-60 mm tall. Rhizomes stout, fleshy, shortly-creeping, white. Leaves radical, clustered; petioles 8-12 mm long, slender; lamina seldom 8-12 × 7.5-11.0 mm, dark green to yellow green, usually unblemished, sometimes marked with darker bronze blotches and/or streaks, broadly oblong to suborbicular, base 2-lobed, subcordate, apex emarginate, margins crenate to crenate-dentate; lobes upturned, ± appressed to and not much shorter than lamina, crenate. Scapes stout, initially subsessile to sessile, soon elongating, and then up to 60 mm tall. Sepals 5, 8-18 × 6-12 mm, white, obovate, obtuse to acute. Stamens 10-15; carpels narrow-ovate in outline; styles rather long, slender. Ripe heads 12-18 mm diameter. Seeds 2-5 per follicle, 1.2- 1.5 mm long, glossy red-brown to dark purple brown, ovate to broadly ovate, ovate-elliptic or elliptic.
Similar taxa
Only reliably distinguished from other, small, alpine Ranunculus when flowering. From Caltha novae-zelandiae readily distinguished when flowering by the oblong-obovate white rather than linear-subulate yellow flowers, and vegetatively by the leaf margins which are crenate rather than shallowly sinuate to entire. Both Caltha obtusa and C. novae-zelandiae are easily distinguished from the uncommon, naturalised marsh marigold (C. palustris) by their much smaller size, turf-forming growth habit, ecology, and features of the foliage and flowers.
Distribution
Endemic. South Island (from Canterbury southwards)
Habitat
In alpine flushes, seepages, around tarns and slow flowing streams. Also found seen in damp areas in open grassland and in similar sites in fell field and herb field
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.
Please note, threat classifications are often suggested by authors when publications fall between NZTCS assessment periods – these interim threat classification statuses has not been assessed by the NZTCS panel.
- 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
Detailed taxonomy
Family
Ranunculaceae
Synonyms
Psychrophila obtusa (Cheeseman) W.A.Weber
Taxonomic notes
New Zealand plants had long been placed in the genus Caltha, they were then referred to Psychrophila, a decision which was over ruled on the basis of a detailed study by Schuettpelz & Hoot (2004).
Endemic taxon
Yes
Endemic genus
No
Endemic family
No
Ecology
Flowering
December - February
Fruiting
February - April
Propagation technique
Difficult. Can be grown in a pot but needs to be kept moist, free of bryophytes and algal growth. Needs plenty of light but resents high temperatures and humidity
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
caltha: From the Greek kalathos ‘goblet’, refers to the form of the flower
obtusa: Blunt
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.
CALOBT
Previous conservation statuses
2017 | Not Threatened
2012 | Not Threatened
2009 | Not Threatened
2004 | Not Threatened
Referencing and citations
References and further reading
Schuettpelz, E.; Hoot, S.B. 2004: Phylogeny and biogeography of Caltha (Ranunculaceae) based on chlroroplast and nuclear DNA sequences. American Journal of Botany 91(2): 247-253.
Attribution
Fact sheet prepared for NZPCN by P.J. de Lange (28 March 2012). Description by P.J. de Lange.
NZPCN Fact Sheet citation
Please cite as: de Lange, P.J. (Year at time of access): Caltha obtusa Fact Sheet (content continuously updated). New Zealand Plant Conservation Network. https://www.nzpcn.org.nz/flora/species/caltha-obtusa/ (Date website was queried)