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Echinodorus aschersonianus Graebner (1911) This plant is occurring in the southern South America (South Brazil, Uruguay, Argentina and Paraguay). Due to this geographical spreading this species has a characteristic seasonal rhythm. Long and short day, heat and cold weather are not unknown for this plant. Travelling aquarium keepers report of very cold water, which were in these degrees of latitude on the way, being substantially below under the water temperatures of our tanks. Echinodorus aschersonianus is obviously a species, which is hardly to maintain in German aquariums. Even considerable botanical gardens do not cultivate this plant. I was very lucky that I could acquire some plants from an old-age pensioner in Magdeburg. Dr. H. Muehlberg (Botanical Garden Halle), who received an adventitious plant from me, confirmed the authenticy. Echinodorus aschersonianus is a smaller to medium sized species, depending of the culture conditions. After my experiences this species is suitable for the foreground of larger tanks or in the middle of smaller tanks. The polymorphology of this plant always surprises me again.
I got short leaves, as well as very long ones, which grew out of the water on long day conditions with strong light and nutritious soil. The blade varies from
rounded oval up to narrowly lanceolate. Because of my experiences in submerged culture blades are growing without lobes at the base, w I am cultivating my plants in a nutritious loam/sand mixture (look: Culture),
covered with washed sand or fine gravel. Pure sand is not accepted, then the plants grow only very small. In my aquariums I use temperatures from 22 to
28 °C, and at all temperatures good growth can be observed. But lower temperatures can be tolerated. I placed a specimen in my garden pond to test
temperature and light requirements. Strong sun lighting initiates red-brown blades when submerged cultivated. But in aquarium culture you can get this
colour only with very strong lighting and low water level. The red colour ho Echin
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hile in emerged culture basal lobes often occurs, forming a
cordate base. Submerged leaves reach up to 15 cm (6 “) long and up to 7.5 cm (3 “) wide. In the literature are larger sheets reported. The plant is expressed light fanatic.
I could observe several times, that shadowing initiate stagnation immediately and the leaves become immediately smaller. Not acting in response to this, the loss of the plant
can occur! To get inflorescences, strong lighting with more than 12 hours (long day) is required. The erect to slightly decumbent inflorescence can reach up to 75 cm (30 “) and
has 2 to 4 whorls with 3 to 6 white flowers each. The flowers have about 17 to 21 stamens. Some few vegetative proliferations are appearing and can be used for propagation.
wever appears only in submerged conditions. Emerged culture shows only small cordate and dark-green blades even during intensive sunshine exposure. At the end
of October the temperature of the pond had only 7 °C, but the plant was still vitally and still got new leaves. However growth became very slow.
I finished my experiment at these
temperatures and placed the plant in one of my tanks inside. There they continued to grow immediately without break. In emerged culture the plants bear high temperatures during full exposure to the sun, but also
very low temperatures having only few degrees above the freezing point. The root formation is very interesting. The roots grow first straight down and than they growth corkscrew-like. I always observed
that new planted specimens are pulled down in the substrate after some weeks up to 2 cm deep into the soil. I believe that the corkscrew-like turned roots are used to pull the plant into the substrate.
odorus aschersonianus can be propagated by adventitious plantlets at the inflorescence. To induce the flowering you must give a substrate with good nutrient conditions and a very strong light of more than 12 hours. Emerged
cultivation is beneficially. The plant seems to be nearly sterile. Although I got many flowers, I got only some few seeds, but I couldn’t germinate them. The reason may be the pollen. Investigations
of the pollen with the electronic-microscope at the Max Planck Institute for Plant Breeding Research showed, that most of the pollen are appa
rently not able to fertilize. Only
some of them are able to do. May be that culture conditions are the reason, because in the literature reports can be found of getting many seeds, which are good germinating.