Sagittaria sagittifolia
Family
Alismataceae
Flora category
Vascular – Exotic
Structural class
Herbs - Monocots
Conservation status
Not applicable
Brief description
A tall marginal aquatic plant, with arrow-shaped leaves and submerged strap like leaves.
Distribution
Only field site from Coromandel Peninsula, Waikato, cultivated elsewhere.
Habitat
Still and slow flowing water bodies.
Detailed description
Tall summer-green perennial dying back to underground parts over winter. Emergent leaves have a distinctive glossy arrow-shape 3 -16 cm x 0.3-7 cm with long basal lobes 2-30 cm long. Petioles are triangular in cross-section. Plants can also produce ovoid floating leaves and strap-like submerged leaves. Rhizomatous with round tubers, up to 3 cm across, produced on these. No flowers seen on New Zealand material.
Similar taxa
Other Sagittaria species. Sagittaria montevidensis also has arrow-shaped leaves but petioles are D-shaped in cross-section and it does not produce creeping rhizomes or tubers. The two other Sagittaria species present in New Zealand (S. subulata and S. platyphylla) do not have arrow-shaped emergent leaves.
Flowering
No flowering plants seen in New Zealand
Flower colours
White
Life cycle
Apparently by deliberate planting and subsequent spread by water movement. Possibly cultivated as a vegetable by some ethnic groups.
Year naturalised
2002
Origin
Native to Asia and Europe.
Reason for introduction
Ornamental pond plant and food plant (edible tubers)
Control techniques
Notify regional council if found
National Pest Plant Accord species
This plant is listed in the 2020 National Pest Plant Accord. The National Pest Plant Accord (NPPA) is an agreement to prevent the sale and/or distribution of specified pest plants where either formal or casual horticultural trade is the most significant way of spreading the plant in New Zealand. For up to date information and an electronic copy of the 2020 Pest Plant Accord manual (including plant information and images) visit the MPI website.
Attribution
Factsheet prepared by Paul Champion and Deborah Hofstra (NIWA).
References and further reading
Champion et al (2012). Freshwater Pests of New Zealand. NIWA publication. http://www.niwa.co.nz/freshwater-and-estuaries/management-tools/identification-guides-and-fact-sheets/freshwater-pest-species.
Kasselmann C (2003). Aquarium plants. Krieger Publishing company, Florida, 518pp.