Cardamine lacustris
Common names
iti
Biostatus
Native – Endemic taxon
Category
Vascular
Structural class
Herbs - Dicotyledons other than Composites
Flower colours
White
Detailed description
Minute ephemeral or annual rosette herb. Stems on young plants very short, on older plants lateral, ascending at first, later prostrate, geniculate, rooting regularly, up to 50 mm long, reaching 0.8-2.0 mm diameter, glabrous or sometimes with sparse, fine, slightly recurved hairs. Leaves glabrous, or with sparse simple hairs on petiole, slightly glossy, dull green or tinged purplish-grey, in rosettes and clustered on stems. Early rosette leaves entire, linear-spathulate; later rosette and cauline leaves pinnatifid, 20-50 mm long; petiole 2-12 mm long, 0.5-1.0 mm wide; terminal lobe narrow-spathulate, 2-5 mm broad; lateral lobes narrowly oblong-spathulate, 4-10 mm long, sometimes single or in uneven numbers, but usually in l-3 subopposite pairs. Peduncle glabrous, 1-2 mm long, reaching 2-5 mm long at fruiting. Sepals suberect, oblong, glabrous, green with narrow pale margins, 1.5-2.0 × 0.6-1.0 mm. Petals white, suberect, oblong- to obovate-spathulate, obtuse, 1.8-2.5 × 0.8-1.2 mm, weakly clawed; limb spreading. Stamens suberect; median stamens usually 2, rarely 4, 1.6-2.0 mm long; lateral stamens 1.0-1.5 mm long. Ovary ellipsoid, 1.0-1.6 mm long; stigma sessile, 0.4 mm diameter; locules each with 5-8 ovules. Silicle elliptic to oblong, l.0-3.5 × 1.0-1.7 mm; valves pale straw coloured, thin, convex, glabrous, not veined or with 1 weak vein. Seeds c.5-8 in one row in each locule, pale to reddish brown, oblong, c.1 mm long.
Similar taxa
Cardamine lacustris is probably closely allied to Cardamine mutabilis (previously known by the tag name Cardamine ‘tarn’), which inhabits the moist margins of tarns, kettles, and streams from Marlborough south through inland Canterbury to Otago and northern Southland. Cardamine mutabilis has a similar over all size and leaf shape to C. lacustris but differs by the long peduncles and a narrow, explosively dehiscent silique 10-15 times as long as its width.
Distribution
Endemic. New Zealand: South Island (Lakes Manapouri, Te Anau and also around small tarns in the eastern part of Fiordland).
Habitat
A lake and tarn dwelling plant. It mostly grows on gently-shelving slopes usually within a sparse turf of other plants where a thin cover of silt or fine sand is lodged among firm and stable cobbles or gravels. In its main lake habitats these are sites which tend to be neither the most sheltered nor the most exposed available, but are subject to moderate wave action and the resultant periodic disturbance of sediments.
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.
- 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 | At Risk – Naturally Uncommon | Qualifiers: EF, Sp
Threats
Apparently not threatened but not that common either. Its presence is dictated by seasonal water levels. Some populations around Lake Manapuri and Te Anau may be threatened. Further research is required.
Detailed taxonomy
Family
Synonyms
Iti lacustris Garn.-Jones et P.N.Johnson
Endemic taxon
Yes
Endemic genus
No
Endemic family
No
Ecology
Flowering
October - May (depends on water levels)
Fruiting
November - July (depends on water levels)
Life cycle and dispersal
Seeds are dispersed by ballistic projection, water and attachment (Thorsen et al., 2009).
Propagation technique
Easily grown from fresh seed. Plants do best kept in a small pot partially submerged in water. Not that attractive for the garden but the leaves are edible and it could be used in cress sandwiches.
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
Where To Buy
Not commercially available
Etymology
cardamine: From the Greek name kárdamon, referring to an Indian spice
lacustris: From the Latin lacus ‘lake’, meaning growing beside a lake
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.
CARLCT
Chromosome number
2n = 48
Previous conservation statuses
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.
- 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.
2017 | At Risk – Naturally Uncommon | Qualifiers: EF, Sp
2012 | At Risk – Naturally Uncommon | Qualifiers: Sp
2009 | At Risk – Naturally Uncommon | Qualifiers: EF
2004 | Range Restricted
Referencing and citations
References and further reading
Garnock-Jones, P.J.; Johnson, P.N. 1987: Iti lacustris (Brassicaceae), a new genus and species from southern New Zealand. New Zealand Journal of Botany 25: 603-610. (the species was initially described as the segregate genus Iti).
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(4): 285-309.
Attribution
Description from Garnock-Jones and Johnson (1987)