Potamogeton ochreatus
Common names
blunt pondweed
Biostatus
Native
Category
Vascular
Structural class
Herbs - Monocots
Detailed description
Aquatic, submerged, rhizomatous perennial herb. Rhizome short, invested with closely set fibrous stipules and roots. Branches erect, at first simple bearing long leaves, then branching up to eight times at leaf axils, branchlets short, produced in spring and elongating in autumn, sometimes rooting from nodes. Stipules to 20 mm long, free, open, obtuse, disintegrating into fibres with age at older nodes (fibres derived from close-set nerves). Leaves all submersed, sessile; lamina 15–100 × 2–5 mm, entire, linear-oblong, obtuse to slightly emarginate, only slightly narrowed to base, membranous, longitudinal nerves 8, fine and close, one in each half usually stronger than the rest. Inflorescence a densely flowered spike up to 15 mm long. Peduncles 20-40 mm long, simple, slender, arising from axils of upper leaves within the short branchlets. Achenes c.3.0 × 2.5 mm, flattened on sides, keel ± 3-ridged, beak rather well-developed, curved.
Similar taxa
Distinguished from all other Potamogeton in New Zealand, except P. crispus by the grass-like, parallel-sided submerged and emergent leaves, bearing numerous, close set, fine longitudinal nerves (these occasionally obscure); and by the fibrous stipules. The naturalised Potamogeton crispus differs by having only submersed, oblong leaves with crimped margins and bearing 3-5 longitudinal nerves.
Distribution
Indigenous. New Zealand: North, South, Auckland Islands. Also Australia and South-East Asia
Habitat
Coastal to lowland in slow moving waters such as rivers, streams, also found in lakes and ponds, especially near lake outlets
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 | Qualifiers: SO
Detailed taxonomy
Family
Potamogetonaceae
Synonyms
None
Endemic taxon
No
Endemic genus
No
Endemic family
No
Ecology
Flowering
November - April
Fruiting
December - May
Propagation technique
Can be grown in ponds and slow-flowing streams. Also an excellent plant for an indoor aquarium. Sometimes can become invasive.
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
potamogeton: River dweller
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.
POTOCH
Previous conservation statuses
2017 | Not Threatened | Qualifiers: SO
2012 | Not Threatened
2009 | Not Threatened
2004 | Not Threatened
Referencing and citations
References and further reading
Moore, L.B.; Edgar, E. 1970: Flora of New Zealand. Vol. II. Government Printer, Wellington.
Attribution
Fact sheet prepared for NZPCN by P.J. de Lange (16 February 2012). Description adapted from Moore & Edgar (1970)
Some of this factsheet information is derived from Flora of New Zealand Online and is used under a Creative Commons Attribution 3.0 New Zealand licence.
NZPCN Fact Sheet citation
Please cite as: de Lange, P.J. (Year at time of access): Potamogeton ochreatus Fact Sheet (content continuously updated). New Zealand Plant Conservation Network. https://www.nzpcn.org.nz/flora/species/potamogeton-ochreatus/ (Date website was queried)