''Hydrocharis laevigata'' is a floating

aquatic plant Aquatic plants, also referred to as hydrophytes, are vascular plants and Non-vascular plant, non-vascular plants that have adapted to live in aquatic ecosystem, aquatic environments (marine ecosystem, saltwater or freshwater ecosystem, freshwater ...

, and is a member of the family

Hydrocharitaceae Hydrocharitaceae is a flowering plant family which includes 14 accepted genera and a total of ca 135 known species (Christenhusz & Byng 2016). The family holds a number of species of aquatic plants, including tape-grass, the well-known Canadian ...

. Common names include West Indian spongeplant, South American spongeplant and Amazon or smooth frogbit. This plant was introduced to North American waterways through use in

aquarium An aquarium (: aquariums or aquaria) is a vivarium of any size having at least one transparent side in which aquatic plants or animals are kept and displayed. fishkeeping, Fishkeepers use aquaria to keep fish, invertebrates, amphibians, aquati ...

s and aquascapes.

Plant origin and distribution

Spongeplant originates from fresh water habitats of tropical and subtropical Mexico

Central America Central America is a subregion of North America. Its political boundaries are defined as bordering Mexico to the north, Colombia to the southeast, the Caribbean to the east, and the Pacific Ocean to the southwest. Central America is usually ...

, the Caribbean, and

South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a considerably smaller portion in the Northern Hemisphere. It can also be described as the southern Subregion#Americas, subregion o ...

. It has been introduced to other parts of the world including California, France, Spain, Sweden, Poland, Japan, western and eastern Australia, Zambia, Zimbabwe, and Java. In

California California () is a U.S. state, state in the Western United States that lies on the West Coast of the United States, Pacific Coast. It borders Oregon to the north, Nevada and Arizona to the east, and shares Mexico–United States border, an ...

it has been introduced as an ornamental pond plant, and has escaped into greater waterways including areas surrounding Redding and Arcata, the

Sacramento River The Sacramento River () is the principal river of Northern California in the United States and is the largest river in California. Rising in the Klamath Mountains, the river flows south for before reaching the Sacramento–San Joaquin River D ...

delta and the

San Joaquin River The San Joaquin River ( ; ) is the longest river of Central California. The long river starts in the high Sierra Nevada and flows through the rich agricultural region of the northern San Joaquin Valley before reaching Suisun Bay, San Francis ...

, and ponds and irrigation canals. It is an invasive species in Chile where it has been found from

Elqui River The Elqui River starts in the west Andes and flows into the Pacific Ocean near the Chilean city of La Serena. It flows through a wine and pisco producing area. Vicuña, the main town of the middle valley, was the home of Nobel Laureate poet Gab ...

in the north to Carlos Anwandter Nature Sanctuary and Ranco Lake in the south.

Description

''Hydrocharis laevigata'' is a floating aquatic plant, which can be mistaken for water hyacinth ('' Eichornia crassipes'') due to their superficial similarity. Juvenile plants grow in rosettes of floating leaves that lie prostrate upon the water surface, a distinguishing character of the juvenile plant is the presence of spongy aerenchyma tissue upon the abaxial surface (underside) of the leaf. Mature plants grow up to 50 cm tall, and have emergent leaves borne on petioles that are not swollen or inflated like the spongy leaf stalks of water hyacinth, which aid in buoyancy. Spongeplant produces stolons which bear gametes. Flowers are small, white, and unisexual. Female flowers have an inferior ovary, the fruit is a fleshy capsule 4–13 mm long and 2–5 mm in diameter, and seeds are 1 mm long, ellipsoid, and hairy. ''H. laevigata'', or Smooth Frogbit, can be distinguished from '' H. spongia'', American frogbit, by flower and leaf characteristics as well as range. The flowers of both species vary greatly over their ranges. American frogbit is not known to occur in western states unlike smooth frogbit. American frogbit in general has more

cordate Cordate is an adjective meaning ' heart-shaped' and is most typically used for: * Cordate (leaf shape), in plants * Cordate axe, a prehistoric stone tool See also * Chordate A chordate ( ) is a bilaterian animal belonging to the phyl ...

-based floating leaves, while smooth frogbit generally has more spatulate floating leaves.

Plant reproduction

''Hydrocharis laevigata'' can reproduce and distribute sexually through flower pollination and seed production, and also vegetatively through fragmentation of stolon segments. The juvenile plants have a great capacity for distribution in that they are small, they float and can be easily and quickly carried along by water currents.

Aquascape use

Amazon Frogbit in captivity has two hazards to its health which aquarium owners can avoid: (1) water droplets on the tops of the leaves can rot the plant (they must be kept dry), and (2) some species of aquatic snail appear to like to eat the spongy material on the bottoms of the plant leaves (keep them near the center of the tank, not against the glass on the edges.)

''H. laevigata'' management

California Department of Food and Agriculture The California Department of Food and Agriculture (CDFA) is a Cabinet (government), cabinet-level agency in the government of California. Established in 1919 by the California State Legislature and signed into law by Governor William Stephens (Am ...

(CDFA) crews which already manage other invasive aquatic plants including '' Hydrilla verticillata'' and ''

Eichhornia crassipes ''Pontederia crassipes'' (formerly ''Eichhornia crassipes''), commonly known as common water hyacinth, is an aquatic plant native to South America, naturalized throughout the world, and often invasive outside its native range.Hydrocharitaceae Aquatic plants Flora of Central Mexico Flora of Southeastern Mexico Flora of Southwestern Mexico Flora of the Caribbean Flora of Central America Flora of western South America Flora of Venezuela Flora of North Brazil Flora of Paraguay Flora of Northeast Argentina Flora of Northwest Argentina Flora of Uruguay Plants described in 1810 Taxa named by Aimé Bonpland Taxa named by Alexander von Humboldt