Helanthium bolivianum "Angustifolius"

Helanthium bolivianum "Angustifolius", better known under its former name Echinodorus angustifolius, originates probably from the Brazilian state of Mato Grosso. Even though the plant grows quite high when submersed it is counted among the "smaller" sword plants forming runners, which have been placed in a genus of their own (Helanthium) different from the genus Echinodorus. Christel Kasselmann and Gitte Petersen identified H. bolivianum "Angustifolius" as a triploid form of Helanthium bolivianum (= Echinodorus bolivianus) by counting its chromosomes. In Europe, this Helanthium species has been known since the sixties of the last century, whereas it is still quite new to the hobby in the USA.
In the trade, another plant is available under the name Echinodorus angustifolius, which differs from the "old" form, staying considerably smaller and forming denser leaf rosettes under the same environmental conditions.

The light green, band-like submersed leaves of H. bolivianum "Angustifolius" grow to a width of about 3 to 4 mm and up to a length of about 50, sometimes even over 60 cm. However, under strong light they tend to stay shorter. The plant reminds strongly of Vallisneria nana.
H. bolivianum "Angustifolius" is not a finicky plant, however, it needs sufficient trace elements to look its best. An iron deficiency often leads to pale colours. It can be remedied by adding a micronutrient fertiliser to the substrate or by well-dosed liquid fertiliser via the water column. Strong light and an additional CO2 fertilisation enhance growth, however, both are not necessarily required, which makes this plant also suitable for tanks with less intensive light and no CO2 fertilisation, where it grows more slowly.

As we already mentioned, Helanthium bolivianum "Angustifolius" reproduces by runners. Once established in the tank it has been known to spread quite invasively and has to be kept in check carefully. Young plants of about 20 cm in height may crop up literally overnight.

Unlike the other sword plants forming runners, H. bolivianum "Angustifolius" is not suitable to create lawnlike structures in the forground. However, it is an ideal plant for the middle- and background as well as the sides of an aquarium and is a great alternative to those Vallisneria species generally used for this purpose.

When cultivated emersed, H. bolivianum "Angustifolius" stays considerably smaller than the submersed form, and it looks more similar to the other forms of the Helanthium bolivianum group. Its emersed leaves are linear to narrow lanceolate, 6 to 15 cm long and 6 to 10 mm wide. Its umbellate or two-whorled inflorescence with tiny white flowers appear mostly under short day conditions, whereas under long day conditions (over 12 hours of light per day) it mostly forms runners.