Classification
Class
Magnoliopsida Brongn.
Order
Alismatales R.Br. ex Bercht. & J.Presl
Family
Ruppiaceae Horan.
Genus
Ruppia L.
 Nomenclature
Scientific Name:
Ruppia megacarpa R.Mason, New Zealand J. Bot. 5: 525 (1967)
 Description

Rhizome relatively unimportant; stems often long, us. with abundant ± zigzag branching. Lvs (4)–10–15–(20) cm. × (0.2)–0.4–0.5–(0.7) mm., bright to olive green, almost filiform but broad-oblong in T.S.; apex bidentate, often most minutely denticulate; sheath (1)–1.5–2.5–(4) cm. long, auriculate. Peduncles to 30 cm. long, often reddish, not notably thicker below fls, becoming spirally coiled as fr. matures. Fls protandrous; carpels 4, occ. 5–6 in upper fl. Podogynes stout, tapering towards base. Achenes 4–4.5–(5) mm. long, gibbous, olive-green, sts red-punctate; mesocarp thick; endocarp tuberculate, black, with 2 triangular apertures opp. to and about on level of top of operculum; beak c. 1.3 mm. long. 2n = 20.

[From: Moore and Edgar (1970) Flora of New Zealand. Volume 2.]

 Biostatus
Indigenous (Non-endemic)
 Phenology

Flowering: Oct.–Feb.; Fruiting: Nov.–Apr.

 Bibliography
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. [Naturally Uncommon]
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. [Naturally Uncommon]
Mason, R. 1967: The species of Ruppia in New Zealand. New Zealand Journal of Botany 5(4): 519–531.