[1] It is a perennial herb that has a slender tap root.

Its stems are 1.5–3.0 mm in diameter and tend to lie down.

[3] It can be distinguished from Alternanthera sessilis by its narrower leaves, its keeled tepals, its shorter staminodes and style.

[3] It is a coastal and lowland species found in both seasonally and permanently wet habitats.

[3] In the 2018 conservation assessment of de Lange and others under the New Zealand Threat Classification System it was classed as "Not Threatened", having a "large, stable population".