Bacopa madagascariensis

Bacopa madagascariensis is native to Madagascar, where it has frequently been found in streams, pools, small lakes and floodplains – submersed, semi-emersed or on wet, often sandy ground along the banks.¹ Its light green, lanceolate to narrowly ovate leaves have a slightly crenate margin and are arranged in decussate pairs on fleshy, sparsely branched shoots; the flowers are violet.¹ A feature cited to distinguish it from B. monnieri, whose leaves taper in a wedge shape towards the stem, is its broad leaf base, which almost clasps the stem.¹²

It tolerates moderately hard, slightly alkaline water but remains smaller there than in the very soft, acidic water of its native sites.¹ If the light is too weak, the shoots lose their leaves from the bottom up, so it needs medium to high lighting.¹ Submersed it grows 5–15 cm tall, which makes it suitable for the foreground.¹