Florida’s Native Aquatic and Wetland Plants

AQUATIC AND WETLAND PLANTS IN FLORIDA

Our state is home to hundreds of native aquatic and wetland plants that live in damp to wet soils, and some even more specialized plants that live entirely in, on, or under water; submersed plants, emersed plants (including grasses, sedges and rushes), and floating and floating-leaved plants. These plants are technically referred to as aquatic macrophytes.

AQUATIC MACROPHYTES

Littoral Zone

The littoral zone refers to the part of a waterbody closest to the shore where light reaches all the way to the bottom. (Courtesy of the Minnesota Dept. of Natural Resources).

Aquatic macrophytes grow in water or in wet areas. Some are rooted in the sediments, while others float on the water’s surface and are not rooted to any substrate. Florida has native and non-native (exotic) aquatic macrophytes. Aquatic macrophytes are aquatic plants large enough to be visible to the naked eye. The term is used to distinguish between aquatic plants and algae. The term “aquatic plants” usually refers to aquatic macrophytes, but it can refer to both. (Note: Large visible algae such as Nitella spp. and Chara spp. are included in the category of aquatic macrophytes.)
Aquatic macrophytes are grouped into three general categories:

submersed aquatic plants
emersed aquatic plants
floating and floating-leaved aquatic plants.

University of Florida Center for Aquatic and Invasive Plants

Submersed Plants

Submersed plants are macrophytes that grow primarily below the water’s surface. Some species are rooted to bottom sediments and others are free-floating. They come in all shapes and sizes and occur in virtually all Florida waterbodies. Environmental factors such as light, water clarity, temperature, pH, nutrient availability and sediment stability affect where submersed plants will grow.

Tape grass (Vallisneria americana) and hydrilla (Hydrilla verticillata) are rooted in the sediments. Coontail (Ceratophyllum demersum) and bladderwort (Utricularia spp.) are free-floating. Some submersed species (tape grass) produce flowers and are pollinated underwater or at the water’s surface. Sago pondweed (Potamogeton pectinatus) has branches and leaves that spread across the water just below the surface. Fanwort (Cabomba caroliniana) produces flowers that float on the surface. Water milfoils (Myriophyllum spp.) have flower stalks that emerge up to six inches above the water. Some submersed plants have several of these attributes: coontail (Ceratophyllum demersum) is a submersed, free-floating plant that produces tiny flowers pollinated underwater.

ROLES OF SUBMERSED PLANTS IN WATERBODIES

The importance of submersed vegetation and the amount necessary to achieve specific management goals are subjects of ongoing research and debate. Submersed aquatic plants perform several important functions:

provide habitat for fish and wildlife
affect nutrient cycles
increase water clarity
stabilize shorelines and sediments
increase or decrease dissolved oxygen concentrations, depending on abundance and the availability of light
contribute to muck accumulation

University of Florida Plant Directory

Vallisneria americana

Eel-grass, tape-grass

Species Overview

Eel-grass or tape-grass is a large, submersed, perennial plant that is native to Florida. Tape-grass is common in still and fast-flowing waters throughout the state. It is a popular aquarium plant. Tape-grass grows from underground runners, and often forms tall underwater meadows. The upper leaf parts are sometimes found floating across the water surface.

Potamogeton pectinatus

Sago pondweed

Species Overview

Potamogeton pectinatus is occasionally found growing in the fresh or brackish water of ponds, lakes and streams from the central and southern peninsula west to the central panhandle of Florida. It blooms from spring to fall (Wunderlin, 2003). The grass-like sago pondweed is a submersed plant that grows from a creeping rhizome. Except for the polar regions and Pacific islands, this species of pondweed occurs worldwide. Sago pondweed grows in fresh, brackish, and saline waters throughout the state. It is found in stagnant ponds, spring-fed rivers, and slow-flowing marshes.

Ceratophyllum demersum

Coontail

Species Overview

This plant is also known as hornwort. Coontail is a submersed, perennial herb. Two species are native to Florida. Having no roots, coontail is free-floating. It grows in sluggish waters throughout the state, and sometimes blooms year-round. Coontail may be confused with fanwort, Cabomba caroliniana.

Cabomba caroliniana

Fanwort

Species Overview

This common Florida native is a rooted, submersed plant. However, it may have submersed and floating leaves, of different shapes. Fanwort generally grows in 3 to 10 feet of water; and is frequently found in ponds, lakes, and quiet streams. Fanwort stems are long and much-branched near the base. They have many slender roots. Fanwort gets its name from the shape of its fanlike, underwater leaves, which are about 2 inches across.

Professional management of aquatic plants in Florida is extensive because both native and non-native submersed plants can reach nuisance levels. An abundance of submersed aquatic plants can adversely affect recreational boating, swimming, and fishing; fish and bird populations; commercial navigation; and flood control.

You can read more about the plants above at the University of Florida Plant Directory

Emersed Plants

Emersed plants are rooted in water-saturated soils or submersed soils near the water’s edge. The leaves and stems grow above the water. During low-water conditions, emersed plants can grow in exposed, damp, sediments. Cattail (Typha spp.), maidencane (Panicum hemitomon), and bulrush (Scirpus spp.) are examples of emersed plants. They can grow from the water’s edge to a depth of 1 to 3 meters (3 to 10 feet).

Some emersed plants are large-leaved, with big spikes of flowers: the arrowheads (Sagittaria spp.) and fire flag (Thalia geniculata). Some are small plants, growing inches above the water (Bacopa spp.). Some are viney, rooted in the mud but crawling across the water: water spinach (Ipomoea aquatica). Some are tall and leafy: the native lake hygrophila (Hygrophila costata). Some can fill a large prairie: bur-marigold (Bidens laevis).

Aquatic grasses, sedges, and rushes are also in the emersed-plant category. Among Florida’s native giant grasses are sugarcane plume grass (Saccharum giganteum) and giant foxtail (Setaria magna). Shorter grasses, such as maidencane (Panicum hemitomon) and knotweed (Polygonum spp.), grow in shallow marshes and lake margins and are extremely valuable to Florida’s fisheries. Sedges include the dominant plant in the Everglades, sawgrass (Cladium jamaicense), and star-rush (Dichromena spp.). Bulrushes include Scirpus spp. and the true rushes of Florida: soft rush (Juncus effusus).

Unfortunately, Florida has many non-native invasive grasses, sedges, and rushes: torpedograss (Panicum repens), paragrass (Urochloa mutica), napier grass (Pennisetum purpureum), and West Indian marsh grass (Hymenachne amplexicaulis).

Emersed plants occur in all Florida waterbodies within a zone from a few feet to hundreds of feet. The zone changes most often in response to changing water levels. When periods of low water are followed by a rapid rise in water level, large sections of emersed plants may be uprooted. Sustained high water can also reduce emersed-plant abundance. In periods of low water, debris from dying emersed plants is a significant factor. Accumulated plant debris can eventually result in the lake becoming shallower, or even transitioning into a swamp or marsh.

ROLES OF EMERSED PLANTS IN WATERBODIES

Emersed plants perform many functions in waterbodies:

provide habitat for wildlife
provide food (seeds and leaves) for waterfowl
reduce shoreline erosion
shed leaves and other plant debris, adding to the sediments. Uprooted plants can form floating islands or tussocks that can pose significant navigational hazards and block access to portions of the waterbody. Tussocks also provide bird and wildlife habitat.

Sagittaria lancifolia

Duck potato

Species Overview

Sagittaria lancifolia is another showy Sagittaria species that is native to Florida. Duck potato is the largest of the arrowheads. Its large leaves and conspicuous flowers make it easy to find in the wild. Duck potato very commonly grows in swamps, ditches, lake and stream margins, and other shallow-water habitats throughout Florida. Duck potato gets its name from the potato-like corms that sometimes form. Corms are bulbous stem parts that grow underground. Duck potato is easily recognized by its large, firm, lance-shaped leaves, which are typically 4 inches wide and up to 2 feet long. The leaf bases taper to the stem. The leaves grow as a fan-like rosette of underground rhizomes. Duck potato flowers are showy and white, with 3 petals. Flowers extend on thick stalks that are often a foot or more above the leaves. The fruiting heads contain many small hooked seeds. Duck potato has large, lance-shaped leaves, it has large, showy, white flowers and its flowers are on stalks that are taller than the leaves.

Thalia geniculata

Fire flag, alligator flag

Species Overview

Fire flag is a large emersed plant that grows from a thick rhizome. It grows in swamps and wet ditches from the peninsula west to the central panhandle of Florida (Wunderlin, 2003). It blooms from summer to fall and occurs almost always (estimated probability 99%) under natural conditions in wetlands. Large simple leaves on long stalks are among fire flag’s most notable features. The leaves are broadly lance-shaped, with broadly rounded bases. They can be up to eight inches wide and more than 2 1/2 feet long. Several leaves growing together are sheathed at the base. Fire flag flowers are paired; that is, two flowering bracts emerge on top of a tall flower stalk. Multiple small purple flowers hang from the bracts. The flowers have three petals.

Schoenoplectus californicus

Southern bulrush, giant bulrush

Species Overview

This sedge looks very much like another tall native sedge, Scirpus validus, soft-stem bulrush. Scirpus californicus is occasionally found growing in ponds, marshes and streams from the northern counties south to the central peninsula (Wunderlin, 2003). It blooms from spring to summer and occurs almost always under natural conditions in wetlands. Southern bulrush is a bulrush sedge from knotty rhizomes; stems to 10 ft. tall, dark green, smooth, slightly 3-angled; leaf blades none, just sheaths; inflorescence at stem tip but appears to be on the side of the top of the stem, irregular drooping branches, each branch having brown spikelets; bract rolled, pointed, to 3 in. long, appears to be continuation of stem; spikelets narrow ovoid, numerous, dark brown, to 1/2 in. long; nutlets grayish, feathery bristles, 2-4, dark red

Cladium jamaicense

Saw-grass

Species Overview

The aptly named saw-grass is a large sedge, known as the dominant plant of the Everglades. It grows in fresh and brackish-water swamps and marshes, and along lake shores throughout Florida. It also can grow well on dry ground. Saw-grass stems typically grow to 6 or 7 feet tall from stout, short runners. The stem is 3-angled but not sharply so, and is hollow. Saw-grass leaves grow from the base and lower stem of the plant. The grey-green leaves are very long, typically 3 feet, and they are stiff and tough. They are flat to v-shaped and relatively narrow: about 1/2 to 3/4 inch wide. Both leaf margins and the underside midrib have cutting saw teeth. Do not attempt to walk through these plants.

You can read more about the plants above at the University of Florida Plant Directory

Free Floating and Floating Leaved Plants

The “floating” category of aquatic macrophytes includes free-floating and floating-leaved plants. Free-floating plants are not anchored in the sediment; they obtain their nutrients from the water. Florida’s native free-floating plants include the world’s smallest flowering plant (a duckweed called water meal, Wolffia columbiana); and two larger duckweeds,small duckweed (Lemna valdiviana) and giant duckweed (Spirodela polyrhiza). Other native free-floating plants are bladderwort (Utricularia spp.) and coontail (Ceratophyllum demersum).

The free-floating plant, water hyacinth (Eichhornia crassipes), is a non-native invasive plant in Florida and has been called “the worst aquatic weed in the world” by experts. In many Florida waters, it requires constant management, known as maintenance control to maintain low levels and keep waterways passable. Water hyacinth has invaded the waters of many countries from its native Brazil; and is profiled here. Salvinia (Salvinia spp.) and water lettuce (Pistia stratiotes) are also non-native invasives that form dense mats covering the water surface.

Floating-leaved plants typically are rooted in the sediments and have leaves that float on the water surface. Water lilies (Nymphaea spp.), spatterdock (Nuphar lutea subsp. advena), American lotus (Nelumbo lutea), and water shield (Brasenia schreberi) are examples of floating-leaved plants. They generally grow along the shoreline, lakeward of the emersed plants.

Floating and floating-leaved plants occur in many Florida waterbodies. Rooted floating-leaved plants can grow completely across shallow waterbodies. The roots of floating-leaved plants provide a stable surface for successful fish spawning.

ROLES OF FLOATING PLANTS IN FLORIDA WATERBODIES

Floating plants and floating-leaved plants perform many functions in waterbodies:

provide food and habitat for fish and wildlife
reduce shoreline erosion
Floating-leaved plant debris contributes to sediment, making a waterbody shallower.
If periods of low water are followed by a rapid rise in water level, the roots of dead floating-leaved plants (called rhizomes) can float to the surface, block access, and hinder navigation. In many cases, masses of floating rhizomes (especially from the native plant spatterdock, Nuphar advena) can form floating islands that grow large enough to support trees. Water hyacinth and water lettuce may completely cover the surface of a waterbody and cause major problems for fish and wildlife habitat, recreation, navigation, and flood control.
Floating and floating-leaved plants are not generally considered a human health concern, but they provide breeding habitat for mosquitoes.
The stems of floating-leaved plants (spatterdock) often contain burrowing insects called bonnet worms that some anglers use for bait.

Wolffia columbiana

Watermeal

Species Overview

Water meal, native to Florida, is a tiny, floating, rootless plant. At 1 to 1.5 mm long, it is the smallest flowering plant on earth. It is occasionally found growing in rivers, ponds, lakes, and sloughs of the peninsula and central panhandle of Florida (Wunderlin, 2003). Water meal is barely discernible to the naked eye and occurs almost always (estimated probability 99%) under natural conditions in wetlands.

R.K. Godfrey says he “sometimes tests for its presence by taking a handful of whatever duckweeds are present and rubbing them between the palms of the hands. If Wolffia is present it gives the feeling of granularness or mealiness.”

Lemna valdiviana

small duckweed

Species Overview

Small duckweeds are floating plants. They are commonly found in still or sluggish waters. They often form large floating mats. There are three types of Lemna occurring in Florida (Wunderlin, 2003). Small duckweed is located throughout the US; and in PR (Kartesz, 1999). Small duckweeds are tiny (1/16 to 1/8 inch) green plants with shoe-shaped leaves. Each plant has two to several leaves joined at the base. A single root hangs beneath.

Spirodela polyrhiza

giant duckweed

Species Overview

Giant duckweed is a native floating plant in Florida. Though very small, it is the largest of the duckweeds. Spirodela polyrhiza is frequently found growing in rivers, ponds, lakes, and sloughs from the peninsula west to the central panhandle of Florida (Wunderlin, 2003). It occurs almost always (estimated probability 99%) under natural conditions in wetlands.

Giant duckweed has two to three rounded leaves, which are usually connected. Giant duckweeds usually have several roots (up to nine) hanging beneath each leaf. The underleaf surface of giant duckweed is dark red.

This plant is easily confused with the exotic plant, Landoltia punctata.

Ceratophyllum demersum

Coontail

Species Overview

Because its feathery leaves are arranged in whorls on the stem, this plant resembles a raccoon’s tail. The feathery, fan-shaped leaves of coontail are best observed in the water. They look feathery because each leaf is divided into many narrow segments. The leaves also have several small teeth, which are found on the midribs.

You can read more about the plants above at the University of Florida Plant Directory