Classification
Class
Magnoliopsida Brongn.
Order
Saxifragales Bercht. & J.Presl
Family
Haloragaceae
Genus
Myriophyllum L.
 Nomenclature
Scientific Name:
Myriophyllum propinquum A.Cunn., Ann. Nat. Hist. 3: 30 (1839)
Vernacular Name(s):
Common water milfoil
 Description

Perennial herb; stems weak, slender, (5)–10–25–(40) cm long, prostrate or erect, usually simple. Lvs usually distinctly dimorphic, sometimes monomorphic. Submerged lvs in whorls of 3–4–(5), ovate to orbicular, (6)–10–20–(25) × 10–16–(25) mm, pectinate; pinnae 10–22, filiform, 5–6–(20) mm long. Aerial lvs in whorls of (2)–3–4–(5), linear, (2)–5–7–(12) × 0.5–1–(1.5) mm, usually flattened but occasionally terete to filiform; margin entire or sometimes weakly toothed. Fls unisexual, ♂ in upper 1–8 whorls, ♀ in lower 2–6 whorls, with usually 1–2 sterile whorls between, occasionally all whorls ♀. Bracteoles ovate, (0.4)–0.5–0.8 × (0.2)–0.4–0.5 mm. ♂ fls sessile or nearly so; sepals 4, ovate, 0.4–0.6 × 0.3–0.4 mm; petals 4, hooded, 1.8–2.7–(3) × c. 1.4 mm. ♀ fls sessile; sepals and petals 0. Frs 0.8–1.1 × 0.8–1 mm, pale yellow-brown or greenish, ± cylindric, smooth apart from scattering of very small tubercles on outer face of mericarps.

[From: Webb et al. (1988) Flora of New Zealand. Volume 4.]

 Biostatus
Indigenous (Non-endemic)
 Phenology

Flowering: Nov.–Apr.; Fruiting: Nov.–May.

 Bibliography
Cunningham, A. 1839: Florae insularum Novae Zelandiae precursor; or a specimen of the botany of the islands of New Zealand. Annals of Natural History 3: 29–34.
de Lange, P.J.; Rolfe, J.R.; Barkla J.W.; Courtney, S.P.; Champion, P.D.; Perrie, L.R.; Beadel, S.N.; Ford, K.A.; Breitwieser, I.; Schönberger, I.; Hindmarsh-Walls, R.; Heenan, P.B.; Ladley, K. 2018: Conservation status of New Zealand indigenous vascular plants, 2017. New Zealand Threat Classification Series. No. 22. [Not Threatened]
de Lange, P.J.; Rolfe, J.R.; Champion, P.D.; Courtney, S.P.; Heenan, P.B.; Barkla, J.W.; Cameron, E.K.; Norton, D.A.; Hitchmough, R.A. 2013: Conservation status of New Zealand indigenous vascular plants, 2012. New Zealand Threat Classification Series 3. Department of Conservation, Wellington. [Not Threatened]
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.