Morava Water Caltrop (Trapa annosa)
The Morava Morava Water Caltrop was described in 1957 as a distinct species.
This flooding aquatic plant only grew in some stagnant and slowly flowing areas of the Morava River, a tributary of the Danube in the Pomoravlje District in central Serbia.
The taxonomic position of this plant is unclear; however, it is very likely identical to the Water Caltrop (Trapa natans L.) (see depiction below), in fact the only difference between the two forms seems to be the length of the horn-like outgrowths on the fruit, which is longer in the Serbian form than in the common Water Caltrop.
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The Water Caltrop itself is now also an endangered species.
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Depiction from: ‘Prof. Dr. Thomé’s Flora von Deutschland, Österreich und der Schweiz, in Wort und Bild, für Schule und Haus. Gera-Untermhaus: F. E. Köhler 1886-1934’
(not in copyright)
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edited: 30.04.2021