ADA – Microcarpaea minima merrill
Microcarpaea minima is a small, tender wetland plant from Southeast Asia, Japan and northern Australia that is able to grow above and under water. It occurs in and by shallow, warm, periodic waters such as puddles and rice fields, also on riverbanks. It is the only species of the genus Microcarpaea and belongs to the same family as Glossostigma (Phrymaceae). It was first introduced as aquarium plant from West Kalimantan by Wim Tomey (Netherlands) and is still a rarity in the aquarium hobby. In the tissue culture line of ADA it is labeled as Microcarpaea minima Merrill; the last part is the author citation of the species name.
In its terrestrial form this plantlet forms low cushions with 3-5 cm long, narrow leaves and small, pale purple flowers on thin stems. The submerged stems grow rather upright, much branched and a little chaotic in all directions, with up to 20 mm long and 1-2 mm wide leaves.
This plant is not too difficult to grow but benefits much from rather strong lighting, soft to medium hard water and CO2 addition. It is considered as thermophilic, so the temperature should be well above 20 °C. The planting of the tender stems may be a little fiddly and is best done with tweezers. The growing, spreading bushes can be kept low by trimming.
Microcarpaea minima may be still little known to aquascapers. It looks decorative as a low, light green bush or small carpet in the foreground or midground and fits well into small tanks. With its narrow, almost needle-like leaves it contrasts from many other foreground plants. Its cushion-like terrestrial form may also be interesting for emersed setups where one may expect its tiny flowers and fruit capsules.