Lindernia rotundifolia

Lindernia rotundifolia is widespread in the tropics, from Africa and Madagascar through South Asia to Central and South America; on land the amphibious species forms prostrate shoots with blue and white flowers.² It differs from the very similar L. parviflora mainly in its shorter-stalked flowers and broadly oval to almost circular leaves with slightly crenate margins; a strain from Sri Lanka is occasionally kept.¹³

Underwater, light determines its growth: strong light produces dense, freely branching bushes, weak light upright, sparsely branched shoots.² The undemanding species benefits markedly from added CO₂ and a complete nutrient supply.² Older, tall bushes are often poorly rooted and easily come loose, so it is recommended to keep the plants at about 15–30 cm by trimming and replanting.² Grown emersed it spreads like a weed and readily self-seeds.²³