Halophila engelmannii (Engelmann's seagrass)

Plate 1 figs. a–h · 3 observations

This species has been photographed under an open licence only 3 times, so some figures below are different views of the same plant, taken on the same day, rather than different individuals. They are usually different parts of it: the leaf, the flower, the bark.

Halophila engelmannii, photographed by Eric Knight — fig. a Eric Knight, CC BY 4.0 / 2022-06-09 / obs. 205043506

Halophila engelmannii, photographed by Lexi Amico — fig. c Lexi Amico, CC BY 4.0 / obs. 81186631

Halophila engelmannii, photographed by Alison Northup — fig. d Alison Northup, CC BY 4.0 / obs. 28912672

Every figure is a research-grade observation under CC0, CC BY or CC BY-SA, rehosted with the photographer’s name, the licence and the observation it came from. Photographs under a NonCommercial licence are excluded from this site and are never stored, which costs us a great many pictures and is not negotiable.

Native range 11 botanical countries

Native distribution of Halophila engelmannii, after Kew’s World Checklist of Vascular Plants. Introduced, extinct and doubtful records are excluded, so this is where the plant is from, not everywhere it now grows. Regions too small to draw at this scale are marked with a dot.

Region	TDWG code	Continent
Bahamas	BAH	SOUTHERN AMERICA
Cayman Is.	CAY
Costa Rica	COS
Cuba	CUB
Puerto Rico	PUE
Trinidad-Tobago	TRT
Florida	FLA	NORTHERN AMERICA
Louisiana	LOU
Mexico Gulf	MXG
Mexico Northeast	MXE
Texas	TEX

Region boundaries approximated from Natural Earth (public domain) and mapped to TDWG World Geographical Scheme for Recording Plant Distributions (WGSRPD) level-3 botanical countries (Brummitt 2001). Indicative, not the official WGSRPD geometry.

Where it actually grows measured, from 33 observations

Condition	5th percentile	Median	95th percentile
Coldest month, mean daily low	10.4 °C	14.6 °C	17.9 °C
Warmest month, mean daily high	28.4 °C	29.4 °C	30.7 °C
Annual rainfall	831 mm	1,307 mm	1,486 mm
Rainfall in the driest quarter	122 mm	188 mm	229 mm

It is not found anywhere that gets close to freezing. This is not care advice and it is not a forecast. It is a measurement: we sampled the climate at every one of the 33 research-grade observations of Halophila engelmannii that carry a coordinate, and this is the range those places actually span. The 5th and 95th percentiles are used rather than the minimum and maximum, because a single cultivated specimen in a heated conservatory should not widen a tropical plant's range to the Arctic.

This is not a hardiness zone. A USDA zone is the average annual extreme minimum temperature. The figure above is the mean daily minimum of the coldest month, which is a different quantity and is typically far warmer. Reading one as the other would place a plant several zones too warm, so we do not publish a hardiness zone, because we do not have one.

Sourcesevery claim on this page

World Flora Online Plant List. accepted name, authority, classification. CC0. Retrieved 2026-07-12.
iNaturalist. photographs and flowering annotations, CC0 / CC BY / CC BY-SA only. per photograph. Retrieved 2026-06-27.
Wikidata. common name (P1843), joined on the World Flora Online identifier (P7715). CC0. Retrieved 2026-07-13.
Kew, World Checklist of Vascular Plants (WCVP v16). native distribution by TDWG level-3 botanical country, and life form. CC BY 3.0. Retrieved 2026-06-04.

We publish what we can source and we say so when we cannot. This page has no care advice and no toxicity claim, because we do not yet have those from a source we can cite.