By Michael Patrikeev, REGUA volunteer
I have been researching the water lilies (Nymphaeaceae) found in Rio de Janeiro State, and here are my conclusions.
There are five native and three non-native species of water lilies in the state of Rio de Janeiro. All five native species: Nymphaea amazonum, N. lasiophylla, N. lingulata, N. pulchella, and N. rudgeana, have white flowers. I do not recall seeing any white water lilies at REGUA. It is hard to say how common these white native species are, but they are definitely not rare. Some occur only in the Atlantic Forest region, from Bahia State to São Paulo and others widely distributed across South America. There is also one non-native species with white flowers, N. lotus. All of the “coloured” water-lilies in Rio de Janeiro are non-native.
The light-blue flowered Nymphaea caerulea, the classical “lotus” of antiquity, is native to the Nile Valley and East Africa. It was introduced to India in ancient times and it is now naturalized throughout tropical wetlands, but is considered an invasive species in Australia. I imagine that N. caerulea is so widespread now its seeds or rhizomes are distributed by waterfowl, from wetland to wetland, but for some reason it does not seem to occur with native species, at least at REGUA.
There is another light-blue flowered species N. capensis, but it appears to be synonymous of the former. The reddish water lily N. rubra, is also non-native (a native of the region of south Asia though to Australia) and is probably an escaped cultivar. Apparently in it’s native range most of flowers are white and whitish, but reddish/purple variety is propagated by growers.