Pontederia vaginalis

Lore & Background

Monochoria vaginalis is native to much of Asia and across many of the Pacific Islands, and it is known in other areas as an introduced species. It is often an invasive noxious weed, and is listed on the United States Federal Noxious Weed List. This aquatic plant is invasive in rice paddies and other water bodies. It is an annual or perennial herb growing in water from a small rhizome, and is quite variable in morphology. The shiny green leaves are up to about 12 centimeters long and 10 wide and are borne on rigid, hollow petioles. The inflorescence bears 3 to 25 flowers which open underwater and all around the same time. Each has six purple-blue tepals just over a centimeter long. The fruit is a capsule about a centimeter long which contains many tiny winged seeds.

Reader's Guide

Pontederia vaginalis is significant as an invasive species, particularly in rice paddies and other water bodies, where it can become a noxious weed. Its listing on the United States Federal Noxious Weed List underscores its impact on agriculture and aquatic ecosystems. The plant's variable morphology and ability to grow as an annual or perennial from a small rhizome contribute to its adaptability. The flowers open underwater simultaneously, and the fruit produces many tiny winged seeds, aiding its spread. In northern Luzon in the Philippines, the whole young plant, except for the roots, is eaten as a vegetable, known locally as hahalung, hakhaklung, or saksaklung. This dual role as both a problematic weed and a food source highlights its complex relationship with human activities.

Did You Know?

• In northern Luzon in the Philippines, the whole young plant is eaten as a vegetable, except for the roots.
• The fruit is a capsule about a centimeter long containing many tiny winged seeds.