At the beginning of the 20th century the building of the Panama channel enabled the inventory of the native vegetation of Panama. Thus 1908 an up to then unknown species was gathered, and
1909 appeared its first description by Small as Echinodorus tunicatus. In the meantime further occurrences are known by herbarium samples from Costa Rica, Colombia, Ecuador and Peru. The spreading emphasis of
this species might be probably Ecuador, Peru and Colombia, as the mass of the herbarium samples proves.
Although the first description was made a long time before, this species doesnâ€™t appear often in the literature. Also the appearance of the plant was only known by drawings or by pictures of
herbarium samples. Pictorial material or living plants were not to be found despite most intensive search. Therefore I decided travelling to Ecuador to find the plant and photograph and gather material for
further investigations. In September/October 2003 it started and I could find in the eastern lowlands of Ecuador, the "Oriente" three locations of this species. Two years later, I found two other
Echinodorus tunicatus is a taxon, which can be found in the undergrowth of the jungle vegetation. It prefers swampy locations at the border of small creaks or in it, but also in
small ponds I found this species. The water level has only few centimetres and because the formation of the area it can be assumed that substantially high-water levels are not
to be expected. The soil consists of more or less strongly decomposed leaves lying on clay in the underground. Due to the small water level the plants were forced to grow emersed constantly.
The rhizomes of the plant are strong (up to 3 cm and 12 cm long) and erect growing. The leaves have a long petiole with a sheath at the base. The blades are ovate-cordate
and the apex acuminate, usually I could find up to 9 veins. The pellucid markings are forming a network independent of the veins. Similarly
Echinodorus horizontalis the blades are horizontally aligned in shady places, in order to catch the sparse light as
much as possible. In free, full sunny places the blades are more erect, in order to reduce the light stress. The blades are of deep green colour, entire and glabrous. Well
developed plants can reach up to 75 cm height and more.
Contrary to Echinodorus horizontalis the inflorescences have a very strong stem (up to 12 mm diameter) and are growing always erect. All inflorescences are without
exception shorter than the leaves, so that they are covered by the foliage. The inflorescence has 3 to 4 (sometimes 5 or 6) whorls, having a lot of flowers. I could count 58 fruits at one whorl! The flowers have a
diameter of approx. 20 mm and they have 22 to 27 stamens. The fruit has a diameter up to 15 mm and contains more than 200 nutlets. The fruit is separating when mature and the seeds drop out. I could
not recognize any vegetative proliferations at the inflorescences. Obviously the reproduction mechanism is optimized for pure seed spreading.
At the natural locations I could not observe submerged plants. Because the similar environmental conditions (I could observe one E. tunicatus between a lot of E. horizontalis) it can be supposed that this taxon can grow submerged too. At the moment
Iâ€™m trying to cultivate Echinodorus tunicatus in my aquarium to test, if it is suitable as aquarium-plant. After 2 years of cultivation I believe, that E. tunicatus can be used as
aquarium plant. It needs a good fertilized substrate and a lot of light. Then the plant grows sufficiant. My plants donâ€™t like to grow out of the water. But the petioles grow
nearly vertically and the blades are horizontally. The plant doesnâ€™t grow as wide as E. horizontalis, so it do need less space in the aquarium.
Echinodorus tunicatus is growing more slowly than Echinodorus horizontalis. From submerged plants I never got inflorescences, so it might be that this plant needs growing out of water to reproduce.
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