Many plants have adapted the ability to survive on dry land as well as in the water. Often this adaptability is what is needed for a species to gain a competitive advantage over other species by growing where the others cannot. These plants are a vital resource for aquatic ecosystems by providing organic matter and shelter for fish, birds invertebrates and small animals. Some species aerate poor soil, helping other species gain a foothold.
The bald cypress, scientific name Taxodium distichum, is a tree that grows in swampy areas of the south easternUnited States. It is a deciduous conifer that can tolerate USDA climate zones 5-10. It can grow to 150 to 200 feet tall under optimal conditions.
When grown in the water it tends of growing knees or pointed growths arising from the roots that stick up above the water level. These are believed to help support the large tree in the mud and to provide oxygen to the root system in anaerobic soils.
It can also be grown in dry locations out of the water. It is good for urban plantings because the roots don't usually disturb streets and sidewalks.
The white mangrove tree, scientific name Laguncularia racemosa, is one of the four trees in a unique set of tropical plants called the mangroves. This is the only group of plants that is classified by their association ecologically. White mangroves tend to grow closer to fresh water, but still within the salt influence from tides. They grow alongside buttonwoods and black mangroves but usually on higher ground. The other member of the set is the red mangrove which tends to grow closer or directly in salt water. Mangrove forests provide critical protection from erosion for tropical shorelines and act as a fish nursery for many fish.
The white mangrove can reach 45 feet tall and produces large amounts of organic matter that becomes the biological basis of the nearby ecosystem. Glands behind the leaves expel salt that was taken up with water in the roots.
American Sponge Plant
The American sponge plant, scientific name Limnobium spongia, is also called North American frogbit and lives in central Mexico and the Gulf Coast all the way north to Delaware and west to the lower extremes of Illinois. It grows along the muddy shore lines of lakes, ponds, and slow flowing rivers. Plants on the shore root in mud and have leaves that reach upright about four inches. As it spreads out into the water it develops small heart shaped flat floating leaves that create dense mats of vegetation. It can be considered an invasive aquatic in many areas.
The nice shape of the floating leaves and their arrangement in a tight rosette shape make these plants a favorite for water garden enthusiasts. Their fast growth provides shelter and food for fish and helps control algae in a pond. L. spongia can be distinguished from it's very close relative L. laevigatum by the heart shaped leaves. L. laevigatum, also known as South American frogbit, has round leaves and requires a tropical climate.