Sagittaria macrophylla
Zucc.Emergent leaves elliptic, rarely sagittate to hastate, 8–25 cm long, 1–8 cm wide; basal lobes when present, attenuate. Inflorescence with 3–5 pseudowhorls of flowers. Bracts 0.7–1.3 cm long. Female flowers with pedicel ascending to spreading, (2.5–)3–11 cm long, distinctly thicker than pedicel of male flowers. Outer perianth lobes reflexed at maturity, 0.7–0.8 cm long; inner perianth lobes white, about twice as long as outer perianth. Filaments of male flowers glabrous. Achene 3.1–3.5 mm long, 2–2.5 mm wide; surface unadorned or with 1–2 narrow wings; apex with persistent base of style 0.4–1.2 mm long.
VRiv, MuF. Native to Mexico. Isolated records in creeks near Numurkah and Kerang in northern Victoria.
Sagittaria macrophylla is thought to be closely related to S. platyphylla, the former distinguished by its extremely long, spreading pedicels and glabrous filaments (Adair et al. 2012). In Victoria these two species co-occur, and potentially hybridise. However, the presence of intermediate plants makes it unclear if both species are present in Victoria, or if these specimens that resemble S. macrophylla are unusual forms of S. platyphylla.
Adair, R.J.; Keener, B.R.; Kwong, R.M.; Sagliocco, J.L.; Flower, G.E. (2012). The biology of Australian weeds 60. Sagittaria platyphylla (Englemann) J.G. Smith and Sagittaria calycina Englemann. Plant Protection Quarterly 27: 47–58.
