Microcarpaea minima

Microcarpaea minima, the only species in its genus, is a delicate marsh plant whose range extends from Japan through South-East Asia to northern Australia.¹² It grows on riverbanks and in shallow, very warm pools or rice fields that hold water only seasonally.¹² It reached the aquarium hobby in 2001 through the Dutchman Wim Tomey, who had brought it back from West Kalimantan; it remains a rarity in the hobby to this day.¹²

Its narrow, almost needle-shaped leaves are only 3–5 mm long on land but up to 2 cm long and light green underwater.¹² Emersed it creeps and forms dense cushions; submersed it stays flat in strong light, whereas in moderate light the shoots turn upright and branch profusely.¹² The warmth-loving species does best in CO₂-rich, soft to moderately hard water with plenty of light; the thin stems are best planted with tweezers, singly or a few together.¹²