A rare flowering highlights this account of -

The truly aquatic
Crinum natans

by Alberto Grossi - Click images to enlarge

On that day I was really lucky. I went to the usual pet shop to buy food for my fishes. As soon I opened the door I was breathless with astonishment. From the top of one of the aquariums a single flower of an immediately identifiable Crinum spread its petals to the neon lights. My first thought was: why doesn't mine flower? Then I asked to the owner of the shop if he had any trigger to make it bloom. He answered me that it was the first time for him too, in fifteen years. I had to take advantage of the occasion and asked permission to take photos. I went back home to get my digital camera and here is the bloom.

Crinum natans Baker (1898, Flora of Tropical Africa 7: 396), is one of the three species of Crinum which is completely aquatic, the others being C. calamistratum and C. thaianum. They spend all their life under the surface of the water but blooming. Other species (i.e. C. americanum, C. erubescens, C. purpurascens, C. campanulatum and many others) have only the roots and the bulb in the water, seasonally or not.

In nature C. natans occurs in perennial streams of Tropical West Africa (Guinea, Cameroun, Sierra Leone, Ghana, Nigeria...). Formally described in 1898, it was found in Fernando Po by G. Mann in 1862 in fresh water, whereas Sir John Kirk, who sent collected bulbs and seeds to the Royal Botanic Gardens, Kew, in 1895, describes it inhabiting rivers with waters at about 25°C (77F). 

Bot. Mag. Tav. 7862, 1902
From the Digital Library of the Missouri Botanical Garden

It has a small ovoid bulb, only 3-4 cm (1.1-1.6") in diameter, offsetting, submerged. The leaves, about 100 cm (39") long and 5 cm (2") wide (usually much less), waved, are arranged in a rosette and float. The flower stalk arises amid the leaves and grows up well above the water level. It carries three to five flowers which are completely white; only the pollen is yellow. The segments are about 10 cm (4") long. It is sweetly fragrant.

Nigerians use the plant to ward off ill health in new-born infants. Only a feeble toxicity has been shown for this species, unlike other members of this genus.

I grow my plants in a large immersed pot. The soil is a mix of coarse sand and rich leaf mold. In winter the water temperature is about 18-20°C (64-68F) and I provide artificial light; in summer the temperatures rises above 30°C (86F) and the natural light is very high. To keep the water moving I immerse a pump. The plants in such way are doing very well and I hope to see flowers from them too, soon.  

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