Located primarily between U.S. 1 and Card Sound Road, this area supports a wide variety of herbaceous plants. The predominant species is the scrub sawgrass (Maricus jamaicensis). Others include: green buttonwood (Conocarpus erecta), small dog fennels (Eupatorium capillifolium), pennywort (Hydrocotyle umbellata), Florida paspalum (Paspallum floridanum), climbing hempweed (Mikania scandens), bushy lippia (Lippis nodiflora), India goosegrass (Eleusive indica) and rosy-camphorweed (Pluchea rosea).
Within the sawgrass marsh are true islands that have been colonized by woody plants. The predominant vegetation found here is: green buttonwood (Conocarpus erecta), Dahoon holly (llex cassine), southern bayberry (Myrica cerifera), cocoaplum (Chrysobalanus icaco), false willow (Baccharis halimifolia), eastern false willow (Baccharis halimifolia), pond willow (Salix caroliniana), sabal palm (Sabal palmetto) and saw palmetto (Serenoa repens).
This zone is south of the sawgrass marsh. The predominant species is the scrub sawgrass (Maricus jamaicensis). Interspersed within this zone are: joint paspalum (Paspalum distichum), seashore paspalum (Paspalum vagianatum), black sedge (Schoenus nigricans), swamplily (Crinum americanum), seashore saltgrass (Distichlis spicata) and saltwort (Batis maritima).
Tree islands in this area contain: green buttonwood (Conocarpus erecta), Dahoon holly (llex cassine), guiana rapanea (Raponea quianen), poison ivy (Toxicodendron radicana), white mangrove (Laguncularis racemosa), pond willow (Salix caroliniana) and muscadine grape (Vitus rotundifolia).
This zone lies to the east and south of the L-3IE Canal. The predominant vegetation is: saltgrass (Disticalis spicata), black rush (Juncus roemerianus) and sea oxeye (Borrichia frutescens).
There are many pools of water where the red mangrove (Rhizophora mangle) grows. Other species that grow within this zone are: green buttonwood (Conocarpus erectus), white mangrove (Laguncularia racemosa), scrub sawgrass (Mariscus jamaicensis), southern milkweed (Asciepias viridula) and eleocharus (Eleocharus cellulosa).
Within the Juncus-Distichlis marsh are tree islands that are colonized by the more woody species. The vegetation found on the slightly higher elevation islands includes: green buttonwood (Conocarpus erectus), red mangrove (Rhizophora mangle), white mangrove (Laguncularia acemosa), black mangrove (Avicennia germinans), nightshade (Solanum verbascifolium), false willow (Baccharis angustifolia), golden leather fern (Acrostichum aurem) and sea oxeye (Borrichia frutescens).
This zone is occasionally colonized by more freshwater species when the rainfall is plentiful. However, storm surges of saltwater quickly kill large numbers of these plants causing this zone to be unstable.
Hypersaline Zone - Scrub (Dwarf) Mangrove (0-1.2m)
This zone contains low open stands of red mangrove (Rhizophora mangle) interspersed with very few white mangrove (Laguncularia racemosa). Saline to brackish water lies in this area for most of the year, except in the center of the tree islands. The species found within this zone are: seashore saltgrass (Distichlis spicata), red mangrove (Rhizophora mangle), white mangrove (Laguncularia racemosa), black rush (Juncus roemeriamus), Virginia glasswort (Salicomia virginica), sea oxeye (Borrichia frutescens).
Within these zones are tree islands that have soil elevations that are slightly higher. The tree islands are dominated by the red mangroves but a large number of white and black mangroves are also found, along with sedges, grasses and herbs around the island margins. The dominant vegetation is as follows: red mangrove (Rhizophora mangle), green buttonwood (Conocarpus erectus), white mangrove (Laguncularia racemosa), black mangrove (Avicennia germinans), saltgrass (Disticalis spicata), black rush (Juncus roemerianus), Virginia glasswort (Salicornia virginica), saltwort (Batis maritima), fuirena (Fuirena scirpordea), sea oxeye (Borrichia frutescens).
Hypersaline Zone - Low Dwarf Mangroves (0-0.5m)
This zone contains very diminutive open stands of red mangrove (Rhizophora mangle). The soil and miter is extremely saline due to reduced freshwater flushing and evaporation of sea water from Card Sound that enters this zone during extreme high tides. The predominant species in this zone are short 12-to-18-inch red mangroves with very few and much reduced leaves. This zone is characterized by a white marl soil of freshwater origin, soil saltiness twice those of the open waters of Card Sound, and extremely poor plant growth. The salt water intrusion and seedling distribution by hurricane tides have established principally red mangroves within this generally stressed environment. These mangroves are physiologically different from the same species that are found growing in the adequately flushed tidal areas. The mangroves of this association are characterized by stunted growth, wide spacing, erratic fruiting, poor seedling survival and an almost complete absence of leaf litter.
Within this zone are tree islands that have slightly higher soil elevations. These islands are dominated by: red mangroves (Rhizophora mangle), white mangroves (Lagunculana racemosa), black mangroves (Avicennia germinans), saltwort (Batis maritima) and black rush (Juncus roemerianus).
Tidal Mangrove Zone (0-10m)
This zone contains dense stands of red mangrove (Rhizophora mangle) and white mangrove (Laguncularia racemosa). The mangroves within this area receive a regular flushing of the sound's tidal waters during seasonal high tides. The resultant cleansing and nutrient flush allow these trees to grow in a more productive manner.
Coastal Band Mangrove Zone (0-20m)
This narrow zone lies landward of the shoreline ridge of Card Sound. The trees found here are: red mangrove (Rhizophora mangle), white mangrove (Laguncularia racemosa) and black mangrove (Avicennia germinans). These mangroves are tall, though somewhat smaller than those on the adjacent coastal ridge. Biomass production in this area is substantial and input to the food chain by leaf fall is considerable. Marine grasses and macroalgae are found here, particularly within the tidal meanders.
Coastal Ridge Mangrove Zone (0-25m)
This zone is a narrow, elevated ridge that partially extends through the EMB site. The ridge hosts red, white and some black mangroves. These trees are tall and productive. The exotic Australian pine (Caesarian ecluisetifolia) has invaded this ridge.