Sesuvium maritimum

Sesuvium maritimum is an annual forb occurring on sandy shores, beaches, dunes, brackish marshes, banks along or near coasts, and waste grounds, primarily in coastal environments from New York south to Florida, west to Texas, Oklahoma and Kansas in the eastern United States, Mexico, Belize, and also in the West Indies. There are an estimated 87 occurrences of this species rangewide, which are threatened by coastal development, invasive species, recreational activities (including off-road vehicles), erosion, sedimentation, flooding, herbivory, sea level rise, and climate change. Sesuvium maritimum is rare to infrequent throughout its range, and may have experienced long-term declines due to coastal development in northern portions of its range. However, this species is also inconspicuous and is easily overlooked. Little is known about rangewide threats and trends, but with a large range extent, a moderate to high number of occurrences, and no obvious intrinsic vulnerabilities, Sesuvium maritimum is considered secure.

Sesuvium maritimum occurs in the eastern United States, primarily in coastal environments from New York south to Florida, west to Texas, and in Oklahoma and Kansas (FNA 2003). This species also occurs in Mexico and the West Indies (Weakley and the Southeastern Flora Team 2025). Range extent was estimated using herbarium specimens, photo-based observations, and NatureServe Network occurrence data collected between 1994 and 2025 (GBIF 2025, iNaturalist 2025, NatureServe 2025, RARECAT 2025, SEINet 2025).

By applying a 1 km separation distance to herbarium specimens, photo-based observations, and NatureServe Network occurrence data documented between 1994 and 2025, it is estimated that there are 87 occurrences rangewide (GBIF 2025, iNaturalist 2025, NatureServe 2025, RARECAT 2025, SEINet 2025). There may be additional occurrences, as this is a small annual species, which is "often overlooked in coastal environments," particularly in northern parts of its range (FNA 2003).

Sesuvium maritimum is threatened by coastal development, particularly in northern portions of its range (Delaware, Maryland, New Jersey, and New York) (FNA 2003). Additional threats include invasive species, recreational activities (including off-road vehicles), erosion, sedimentation, flooding, herbivory, sea level rise, and increased storm frequency and severity due to climate change, though there is insufficient data, including anecdotal accounts, to understand scope and severity of threats for this species (NatureServe 2025).