Common water milfoil
Vascular – Native
Herbs - Dicotyledons other than Composites
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.
2n = 14
Current conservation status
The conservation 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). 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.
2012 | Not Threatened
Previous conservation statuses
2009 | Not Threatened
2004 | Not Threatened
Weak aquatic or semiaquatic or terrestrial herb (50-)100-250(-400) mm tall; stems weak, slender, 1.0-1. 5(-3.0) mm diameter, rooting at lower nodes; glabrous. Leaves distinctly dimorphic. Submerged leaves in whorls of 3-4(-5), ovate to orbicular in outline, (6-)10-20(-25) × 10-16(-25) mm, pectinate with 10-22 filiform pinnae 5-6(-20) mm long, with distinct petiole 1-2 mm long. Emergent leaves in whorls of (2-)3-4(-5), linear, (2-)5-7(-12) × 0.5-1.0(-1.5) mm, usually flattened but occasionally terete to filiform, spreading or slightly curved upwards, margin entire or sometimes weakly toothed. Rarely, all or most emergent leaves pinnatifid, 4-5 ×1.5-3.5 mm wide with pinnae to 1.5 mm long. Transitional leaves usually 1-2(-4) whorls only. Inflorescence an indeterminate spike with the unisexual flowers borne singly in axils of the emergent leaves. Each whorl contains flowers of 1 sex only, male in upper 1-8 whorls, female in lower 2-6 whorls, with usually 1-2 sterile whorls between. Occasionally all whorls (up to 20) contain female flowers only. All flowers subtended by 2 bracteoles. Bracteoles ovate, (0.4-)0.5-0.8 × (0.2-)0.4-0.5 mm wide, slightly laciniate towards tip or entire. Male flowers 4-merous, sessile or becoming shortly pedicellate. Sepals 4, ovate, 0.4-0.6 × 0.3-0.4 mm, weakly toothed near apex. Petals 4, hooded, very weakly keeled, 1.8-2.7(-3.0) × 1.4 mm, becoming reflexed and inrolled after anthesis. Stamens 8; filaments 1-2 mm long, elongating after anthesis; anthers yellow, linear-oblong, 1.7-2.4 × 0.4-0.5 mm, antisepalous anthers c. 0.2 mm longer than antipetalous ones. Styles 0. Ovary vestigial. Female flowers 4-merous, sessile. Sepals, petals and stamens 0. Styles 4, clavate, 0.2-0.3 mm long, stigmas occupying most of length of style, white, fimbriate. Ovary 4-merous, oblong, 0.7-0.8 mm long (excluding styles), 0.7 mm wide; carpels cylindrical, smooth, with styles on outermost corners. Fruit pale yellow-brown, cylindrical, sessile, splitting at maturity into 4 mericarps. Mericarps 0.8-1.1 mm long, 0.4-0.5 mm diameter, smooth apart from scattering of very small asperities on outer face, crowned by persistent base of style.
Easily grown from fresh seed and rooted pieces. An excellent plant for pond, slow flowing stream or fish tank.
myriophyllum: Many leaves
propinquum: Very like the next species
Fact Sheet Prepared by P.J. de Lange (1 November 2009). Description based on Orchard (1979)
References and further reading
Orchard, A.E. 1979: Myriophyllum (Haloragaceae) in Australasia. 1. New Zealand: a revision of the genus and a synopsis of the family. Brunonia 2: 247-287.
Please cite as: de Lange, P.J. (Year at time of access): Myriophyllum propinquum Fact Sheet (content continuously updated). New Zealand Plant Conservation Network. https://www.nzpcn.org.nz/flora/species/myriophyllum-propinquum/ (Date website was queried)