Flora of New Zealand Series

1

Leaves with longitudinal nerves well separated, laminae mostly elliptic to oval, or, if oblong, crimped

Leaves with longitudinal nerves close, laminae all linear with flat margins

2

Leaves of 2 kinds, submersed leaves narrower, floating leaves broad-oval; achenes with strong keel and short beak

Leaves not differing greatly throughout plant, either mostly floating, elliptic, or all submersed, oblong, crimped; achenes either not obviously keeled, or if keeled then with very prominent beak

3

Leaves all submersed, oblong, margins crimped, longitudinal nerves 3-5

Leaves mostly floating, elliptic, margins flat, longitudinal nerves (11) -13-21

4

Leaves filiform, < 2 mm wide; stipules membranous, adnate below to leaf; inflorescence discontinuous

Leaves linear-oblong, > 2 mm wide; stipules fibrous, free; inflorescence continuous