''Hydrocharis spongia'', commonly known as American frogbit, is a species of

flowering plant Flowering plants are plants that bear flowers and fruits, and form the clade Angiospermae (). The term angiosperm is derived from the Ancient Greek, Greek words (; 'container, vessel') and (; 'seed'), meaning that the seeds are enclosed with ...

in 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 ...

. It is native to the central and southeastern United States, where it grows in the Lower Mississippi Valley as far north as Illinois, and on the Southern Coastal Plain from Texas to Delaware. It is occasionally found elsewhere as a

waif A waif (from the Old French , )Dictionary.com Unabridged (v 1.1). Random House, Inc. http://dictionary.reference.com/browse/waif (accessed: June 02, 2008) is a person removed, by hardship, loss or other helpless circumstance, from their original ...

.Biota of North America Program, 2013 county distribution map
Image It grows in the slow-moving water of streams, bayous, and lakes from sea level up to 100 meters elevation. The plants are herbaceous, growing up to 50 cm long. Heart-shaped or nearly rounded leaves are floating or emersed, 1–3 in (2–7 cm) in diameter. The leaves have two forms, often on the same plant. Floating leaves have a thick layer of spongy

aerenchyma Aerenchyma or aeriferous parenchyma or lacunae, is a modification of the parenchyma to form a spongy tissue that creates spaces or air channels in the leaves, stems and roots of some plants, which allows exchange of gases between the shoot and ...

on the underside, while the emerged leaves lack the aerenchyma. Plants are mostly

dioecious Dioecy ( ; ; adj. dioecious, ) is a characteristic of certain species that have distinct unisexual individuals, each producing either male or female gametes, either directly (in animals) or indirectly (in seed plants). Dioecious reproduction is ...

and sometimes

monoecious Monoecy (; adj. monoecious ) is a sexual system in seed plants where separate male and female cones or flowers are present on the same plant. It is a monomorphic sexual system comparable with gynomonoecy, andromonoecy and trimonoecy, and contras ...

and flower in summer and fall, mostly on plants with emersed leaves. Fruits are 4 to 12 mm diameter form from pistillate flowers, and once pollinated the peduncle becomes recurved to push the developing fruit below the water surface.

References

{{Taxonbar, from=Q39028589, from2=Q2756959 Hydrocharitaceae Freshwater plants Endemic flora of the United States Flora of the Southeastern United States Flora of Illinois Flora of Missouri Flora of New York (state) Flora of Oklahoma Flora of Texas Plants described in 1807