Kingdom: Plantae
(unranked): Angiosperms
(unranked): Eudicots
(unranked): Asterids
Order: Lamiales
Family: Plantaginaceae
Tribe: Gratioleae
Genus: Bacopa
Species: Bacopa lanigera
Common names: Hairy Bacopa, Hairy water hyssop, Waterhyssop, Woolly Bacopa , Water Hyssop

Bacopa lanigera is an aquatic, marsh plant found in Brazil and Paraguay, South America and is now found throughout the world as an aquarium plant.
This plant is capable of growing underwater, on the water surface, or on land. It usually produces numerous branched creeping stems that spread across muddy soil or float on shallow water. It has escaped in Australia and is found growing in and around farm dams and along small or slow-moving waterways. It is on Australia’s and New Zealand’s watch as a potential aquatic weed.
It has small glossy green leaves (8-20 mm long and 6-15 mm wide) obtuse leaves that are alternate and are attached directly to the stem without a petiole (stalk). The leaves have entire margins. 
The thick stems and branches are densely covered in relatively long spreading hairs. 
When submerged the leaves are light-green, and roots may develop where the leaves are attached. Underwater the stems tend to be red in colour. 
Bacopa lanigera when it receives frequent sunlight it produces 10 mm long flowers with five bluish-purple petals. They are arranged singly in the leaf forks near the end of the branches. They are borne on slender stalks (5-20 mm) long that are also hairy. Each flower has two green bracts at its base and the petals are formed into a short tube with five spreading lobes at the tip. The fruit is a small capsule (4-5 m long) containing numerous tiny seeds.

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Bacopa lanigera-001.JPG 

Thanks to Wikipedia for text and information: https://creativecommons.org/licenses/by-sa/3.0/