Water lettuce: (scientific name: pistia)

Overview: Water lettuce is a free-floating freshwater tropical or subtropical plant that spreads along the surface of the water. This is a very undemanding aquatic plant and probably one of the most productive freshwater plants in the world. First discovered from the river Nile in Africa it is now cultivated artificially around the globe. True to its name, Water lettuce resembles the appearance of the edible lettuce plant used in salads worldwide. Mostly grown in ponds and lakes for providing shade and habitat for fishes, water lettuce grows very fast and is not suitable for compact aquariums and fish tanks.

Appearance: Water lettuce has fine hairs all over the leaves, which, make them look velvety to touch and are green in color. The leaves are light and arranged in spiral whorls that contribute to the lettuce like appearance. Leaves can grow up to 6 inches in width, 10 inches in length and have large prominent veins. The fine hairs form basket-like structures trapping air bubbles, increasing the plant's buoyancy and helping them float. The roots hang below the floating leaves submerged under water. Water lettuce plant bears dioecious flowers that are often concealed behind the thick foliage.

Hard/Soft plant: Soft plant.

Ideal water temperature conditions: Water lettuce thrives in tropical temperatures between 26 and 33 degrees Celsius. Water lettuce plant is not compatible with freezing low temperatures and the leaves start to decay.

Lighting conditions: Water lettuce grows exponentially when exposed to high lighting levels and therefore to control its proliferation, low to medium lighting intensity is highly recommended.

Ideal pH water conditions: Water lettuce prefers pH levels between 6.5 and 7.5 for optimum growth.

Functions and advantages:

1) Submerged portions of Water lettuce provides a natural habitat for various macro and microinvertebrates that are consumed by fishes and other wildlife species.

2) Water lettuce provides cool shade to the pond and fishes.

3) The floating and partially immersed big leaves of water lettuce provide ideal habitat for spawning fishes to lay eggs and also lets the shy fishes and smaller fries to hide.

4) The water lettuce plant helps to enrich the water by generating oxygen and eliminating the growth and formation of algae.

5) Water lettuce is a food source of fresh water turtles in the Amazon basin.

Did you know ?

Water lettuce proliferates via asexual reproduction. After fertilization, small green berries are formed. A stunted stolon connects the parent and offspring plants and dense mats are formed on the surface of the water.