Plants in Hawaii came by air and sea as seeds and spores that floated on the ocean currents or were carried by migratory birds to this island. When the Polynesians arrived in Hawaii they found lush islands teeming with native flora and fauna, some of them found in no other place on earth. One plant, the Tephrosia purpurea known as Auhuhu or Poison Fish plant was introduced by the Polynesians to these fabled islands.
About the Poison Fish Plant
This flowering plant is in the pea family, Fabaceae, and is found in the lowland tropics. It prefers dry, rocky, or sandy soils and is considered a common wasteland weed. It is an erect or spreading annual or short-lived perennial herb. The leaves of this plant contain rotenoid tephrosine which stuns fish but not mammals. Rotenonoids are classified by the World Health Organization as moderately hazardous. They are mildly toxic to humans and other mammals, but extremely toxic to many insects (hence their use as an insecticide) and aquatic life, including fish. This higher toxicity in fish and insects is because the lipophilic rotenonoid is easily taken up through the gills or trachea, but not as easily through the skin or the gastrointestinal tract.
Medicinal Uses and Fishing
The Hawaiians mix the leaves or buds with salt, baked coconut, and water and apply this mixture to treat skin diseases and cuts. The dried plant was used as a diuretic and to treat bronchitis. A decoction of the plant was used as a treatment against intestinal worms and to relieve inflammation and bodily pains.
In Hawaii, fish trapped in tidal pools at low tide were sometimes caught with mild toxins obtained from the Tephrosia purpurea plant. The whole plant or the root, stem, and bark is crushed into bits, either with a mortar and pestle or with rocks found by the shore. The materials were then scattered in tide pools around the base of rocks and into holes where fish might hide. In a few minutes, the small fish that were present would float to the surface and could be picked up.
Did You Know...
The plant is used as green manure for vegetables, rice, coconut, and banana. When used in this way it reduces oil salinity and lowers plant ph.
This plant flowers all year long in Java.
The seeds are used in China as a substitute for coffee.
It is also known as wild indigo
In Africa, shepherds use crushed plants to treat snake bites.
An orange-brown dye can be made from the leaves of this plant.