Johnson's Seagrass (Halophila johnsonii)
Johnsons' Seagrass Bed: Photo Credit Lynn Lefevbre
Johnson's seagrass can be identified by its smooth margins, spatulate leaves in pairs 0.25 to 1 inch (0.5-2.5 cm) long, a creeping rhizome (a horizontal subterranean plant stem, like the runners on a strawberry plant) with petioles, sessile (attached to their bases) female flowers, and longnecked fruits. The male flowers are unknown.
Outstanding differences between Johnson's seagrass and other similar species are its distinct asexual reproduction and leaf shape and form. The species is known to reproduce only asexually and may be limited in distribution because of this characteristic. Johnson's seagrass plays a major role in the health of "benthic" resources as a shelter and nursery habitat. It has been documented as a food source for endangered West Indian manatees and threatened green sea turtles. NOAA's National Marine Fisheries Service (NMFS) continues to conduct ecological research on Johnson's seagrass to better understand its life history and inform conservation decisions affecting the seagrass ecosystems.
ESA Listing Information
Supplemental Information on Johnson's Seagrass
For additional information on this subject contact: Shelley Norton (727) 824-5312