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Water spangles floating on surface of flood plain of Brooker Creek in Tarpon Springs, FL.

Commonly Confused Floating Aquatic Plants of Florida

Florida is home to a variety of floating aquatic plants. These plants are supported by the many different wetland biomes that can be found here. Many of these species can be found in swamps or marshy wetlands. Floating aquatic plants can usually be easily identified, however some of these plant can be difficult to tell apart. With some information and practice, soon you will be able to distinguish between these species with ease!

Water Spangles vs Duckweed


Water spangles (Salvinia minima) is a highly invasive species of floating fern. This plant can out-compete other native floating plants and harm Florida’s wetland ecosystems. Water spangles has slightly folded leaves with bristles on the surface, giving it a rough-looking texture. They are no more than an inch in size and usually are found in large clumps floating on the surface of slow moving streams and lakes. Water spangles reproduce by cloning themselves over and over, and can increase in numbers at an alarming rate. These plants were accidentally introduced from use in aquariums and water gardens as a decorative plant and can now be found throughout Florida.

Duckweed (Landoltia punctata, Lemna spp., Spirodela polyrhiza) is another common floating plant, but is native to Florida.  It also has a green leaf but has a flat, smooth surface, and is no more than 1/16th of an inch in size. So, much smaller than water spangles. Duckweed can also been seen in clumps floating in rivers and lakes in Florida. Duckweed is actually a very tiny flowering plant. This plant is an essential food source to many different species of fish and birds.

The easiest way to tell these two apart is by simply looking at the leaves. The leaves of water spangles are significantly larger than that of duckweed. You can also feel to see if the leaf is smooth and flat or if it has tiny bristles on top. If the leaf is smooth and flat then it is duckweed and if it has bristles and has a rough surface it could likely be water spangles!

If you’re more of a visual learner, check out this video.

Spatterdock vs Water Lily
Spatterdock (left) and water lily (right).

Spatterdock (left) and water lily (right).

The easiest way to tell these two apart is to look at the flowers. The flowers of spatterdock (Nuphar advena) are yellow and slightly closed, while the flowers of water lily (Nymphaea spp.) are fully opened and can be yellow, white or purple. Although easy to tell apart when flowering, it is much more difficult when they are not! When they are not flowering look at the leaves. The leaves of spatterdock are longer than they are wide and the notched lobes are rounded not pointed (like water lily).  Both of these plants play an important role in the ecosystems they inhabit as they provide shelter to many species of fish, frogs, and turtles.

Water Hyacinth vs Frog’s-Bit


Water hyacinth (Eichhornia crassipes) was also introduced in water gardens because of its very pretty purple flowers. The leaf stalk has a smooth, fleshy and spongy texture. Leaves of this plant are round and the undersides of young leaves are smooth. This invasive, floating plant out-competes other native plants and can impair water flow in the areas it inhabits.

Frog’s-bit (Limnobium spongia) is another commonly found floating plant, but is native to Florida. This plant has almost hidden white flowers, a smooth and ridged leaf stalk with rounded, heart-shaped leaves. The underside of young leaves of frog’s-bit have a distinct, spongy, red disk. Frog’s-bit can be found anywhere in Florida and inhabits slow or non-moving bodies of fresh water. Also, this plant tends to clump up on the surface of water and can cause some harm if not kept in check.

When flowering it is easy to tell these two apart, however when they are not flowering it can be tricky. If flowers aren’t present, look at the roots; roots of water hyacinth are black while the roots of frog’s-bit are white. If you’re able to examine the plants in-hand, feel the leaf stalk. The leaf stalk of water hyacinth has a fleshy, spongy texture while frog’s-bit’s leaf stalk is rigid and smooth. You can also look for the spongy, red disk underneath young leaves of frog’s bit.

If you’re more of a visual learner, check out this video.

In Summary

Plant identification can be tricky, especially when there are two species that look similar. It is our hope that this blog helps you to be more confident in properly identifying the species highlighted here.

If you enjoyed this series and would like to read more about commonly confused plants and animals in Florida, you can find more here: