Common Name: Khai Nam
The floating plant, growing with the much larger Spirodela polyrhiza
Photograph by: Marshman
Khai Nam is one of the smallest flowering plants in the world. An aquatic plant, it floats upon the surface of still or slowly flowing water[
The plant is cultivated as a vegetable in Burma, Laos and Thailand[
]. It has been recommended for commercial cultivation, especially in tropical areas, because of its rapid multiplication and high nutritional value[
]. Plant densities of over two million plants per square metre have been found[
Although no specific mention has been seen for this species, it belongs to a family where most of the members contain calcium oxalate crystals. This substance is toxic fresh and, if eaten, makes the mouth, tongue and throat feel as if hundreds of small needles are digging in to them. However, calcium oxalate is easily broken down either by thoroughly cooking the plant or by fully drying it and, in either of these states, it is safe to eat the plant.
People with a tendency to rheumatism, arthritis, gout, kidney stones and hyperacidity should take especial caution if including this plant in their diet[
Tropical areas of Africa and Asia, widely naturalised in other warm regions of the world.
Floating on quiet waters[
]. A rare native of southern Britain, growing in still waters[
A pond plant, it requires a sunny position in still water that is rich in nitrates and lime[
It over-winters in temperate areas by means of resting buds which sink to the bottom of the pond in the late autumn and rise again in the spring[
Reports for the uses of this plant are often wrongly cited under Wolffia arrhiza[
Leaves - cooked. An excellent flavour, they taste somewhat like a sweet cabbage[
]. The leaves are very nutritious, containing about 20% protein, 44% carbohydrate. 5% fat and are rich in vitamins A, B2, B6, C and nicotinic acid[
Seed - we have no information on this species but, since it can spread rapidly by division, it really needs no extra help once it is in a pond.
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