''Monochoria vaginalis'' is a species of flowering plant in the water hyacinth family known by several common names, including heartshape false pickerelweed and oval-leafed pondweed. It is native to much of Asia and across many of the Pacific Islands, and it is known in other areas as an

introduced species An introduced species, alien species, exotic species, adventive species, immigrant species, foreign species, non-indigenous species, or non-native species is a species living outside its native distributional range, but which has arrived there ...

. It is often an invasive

noxious weed A noxious weed, harmful weed or injurious weed is a weed that has been designated by an agricultural or other governing authority as a plant that is injurious to agricultural or horticultural crops, natural habitats or ecosystems, or humans or liv ...

, and is listed on the United States Federal Noxious Weed List. An

aquatic plant Aquatic plants are plants that have adapted to living in aquatic environments (saltwater or freshwater). They are also referred to as hydrophytes or macrophytes to distinguish them from algae and other microphytes. A macrophyte is a plant that ...

, it is invasive in rice paddies and other water bodies. This is an annual or perennial herb growing in water from a small

rhizome In botany and dendrology, a rhizome (; , ) is a modified subterranean plant stem that sends out roots and shoots from its nodes. Rhizomes are also called creeping rootstalks or just rootstalks. Rhizomes develop from axillary buds and grow hori ...

. It is quite variable in

morphology Morphology, from the Greek and meaning "study of shape", may refer to: Disciplines *Morphology (archaeology), study of the shapes or forms of artifacts *Morphology (astronomy), study of the shape of astronomical objects such as nebulae, galaxies, ...

. The shiny green leaves are up to about 12 centimeters long and 10 wide and are borne on rigid, hollow petioles. The

inflorescence An inflorescence is a group or cluster of flowers arranged on a stem that is composed of a main branch or a complicated arrangement of branches. Morphologically, it is the modified part of the shoot of seed plants where flowers are formed o ...

bears 3 to 25 flowers which open underwater and all around the same time. Each has six purple-blue

tepal A tepal is one of the outer parts of a flower (collectively the perianth). The term is used when these parts cannot easily be classified as either sepals or petals. This may be because the parts of the perianth are undifferentiated (i.e. of very ...

s just over a centimeter long. The fruit is a capsule about a centimeter long which contains many tiny winged seeds.

References

External links

Jepson Manual TreatmentPhoto gallery
Pontederiaceae Aquatic plants Invasive plant species in Sri Lanka Taxa named by Nicolaas Laurens Burman {{commelinales-stub