1. Sepals at least 4 mm long (usually 5); seed with a thin wing ca. 0.3 mm broad.
S. media
1. Sepals mostly not over 4 mm (usually 2–3.5); seed usually wingless.
2. Stamens 1–3 (rarely more); plant of saline habitats.
S. marina
2. Stamens usually 10 (or some aborted); plant of non-saline habitats.
S. rubra
All species found in Spergularia
Citation:
MICHIGAN FLORA ONLINE. A. A. Reznicek, E. G. Voss, & B. S. Walters. February 2011. University of Michigan. Web. June 26, 2022. https://michiganflora.net/genus.aspx?id=Spergularia.