Hemianthus callitrichoides
aka dwarf baby tears was imported from Cuba in 2004 by Tropica and has
thus found its way into the hobby relatively recently. The plant was
discovered by Holger Windeløv around 90 km to the East of Havana in a
rocky river during the dry season. The dense, cushion-like population
rooting in gravelly substrate was growing around 50 cm above the
waterline, and he safely assumed that during the rainy season, the
entire population is submersed in waters up to 1 m deep, with a strong
current. Its leaf size of only four to three millimetres makes this
Hemianthus species the smallest aquarium plant in the world. For several
years it has been among the most popular aquascaping plants.
The
majority of Hemianthus callitrichoides plants you can buy in the trade
were cultivated emersed and have roundish leaves. In the axils,
sometimes you can see tiny white flowers. The submersed form looks quite
similar, with a low carpet- or cushionlike growth. Its leaves are
smaller and a bit narrower. It has more or less upright but very short
stems with opposite leaves (two leaves per node), and, at the same time,
creeping as well as overhanging shoots. On both the latter, the leaves
are frequently found to form whorls of three per node. When planted in
small patches a few centimetres apart in the well-lit foreground of an
aquarium, Hemianthus callitrichoides grows to form a dense, bright green
plant carpet within 3 to 4 weeks. Planted in an elevated place it forms
decorative overhanging shots.
H.
callitrichoides has a more compact growth in relation to light
intensity. Its optimum temperature lies around 25 °C, however, it also
tolerates temperatures in the range between 20 and 28 °C. It is not
always necessary to fertilise H. callitrichoides with CO2, however, the
plant grows much healthier with it. It is susceptible to iron
deficiencies, whose symptoms are yellow shoot tips. It should also be
supplied with a sufficient amount of macronutrients, especially nitrate.
Its
relative hardiness and its very nice appearance make H. callitrichoides
a highly attractive and recommendable aquarium plant. It is not only
suitable for carpet-like structures in the foreground, but also for
layouts with many stones as a nice accent in the crevices, where it
reminds the onlooker of alpine cushion plants. It can even be attached
to driftwood, where it forms large bright green cushions with
overhanging shoots. This tiny plant is highly suitable for nano tanks.
Under sufficiently intense light, Hemianthus callitrichoides can also be
cultivated above the waterline, where it generally forms more compact
cushions than under water. In an open tank, it may be attached along the
waterline of driftwood or rocks sticking out of the water.