Today the caltrop (also called water chestnut) is mainly famous for being an endangered plant that is listed in the Red Book. There was a time when it grew everywhere around Russia, Ukraine and Belorussia. You can find a lake named Orekhovoe (eng. Water chestnut Lake) close by Murom town. It was called so because it skinned over with a water chestnut. Before the caltrop was ground into flour, boiled it in salty water or people just baked on fire. They even feed pigs with it. The caltrop nuts have 50% starch content, also have oil and glucose. Caltrop is a good medicine against dysentery.
Being a water plant it forms the leaf bud that is similar to the birch one. The leaf stalks vary in size and the plant itself looks pretty. You can see an “air bladder” on the stalk crown. These blow-ups support first the plant and then the fruit on it. The fruits are the 2-2,5cm high nuts with a thick skin and 2-4 brittle horns on it.
The flexible stem sticks to the bottom like an anchor with its year earlier nut and thin brown roots. It can easily separate away from the soil and swim. Whenever it touches the soil, it gets rooted again.
The caltrop springs out not the way other plants do this. The plumule first rises up and as soon as it has the stem it turns down and sticks aground. The caltrop flowers are open only in the mornings and only for a few hours and sometimes it doesn’t open at all. It’s more likely that the pollination procedure is held inside the flower.
The caltrop plant grows in the ponds in Europe, Asia and Africa. The most nuts are collected from the Nyassa Lake, Central Africa. Its name means “the caltrop dwelling”. This plant is bred in Japan, India and China.