Introduction Among the fl oral biodiversity the water plants and their groups get the most anthropogenic infl uence and disappear because they are rather sensitive indicators of the condition of aquatic environment. That is why most of them are included to the “Red lists” or “Red books” of the different regions of the world. One of the ways of protecting the plants of Nymphaea L genus is their introduction in the greenhouse and open soil conditions. The important stage for positive results is a complex studying of bioecological pecularities of the species and their ontogenesis in conditions of ex situ. Material and methods the object of our researches was Nymphaea gigantea Hook (plant) taken from the collection of the Botanical garden named after O.V. Fomina. For more close studying the plants of this genus the methotology of modeling the control conditions of existence (similar to natural conditions) in artifi cial ponds in greenhouse conditions of the Botanical garden was used. The systematic analysis of the members of the family was carried out. The biomorphologial peculiarities of this plant were described. The periods of ontomorphogenesis were studied. For anatomical studies the leaves, fl oating on the water surface, of N. gigantea were used and collected in the phase of 2-3 days after opening. The samples were fi xed by Chamberlain. They were embedded in gelatin by the standard method and were made leaf cross-sections (a 10-15 microns thick) by the freezing microtome. The sections were stained with safranin. Also, the maceration of leaves for studying the structures of epidermis of the adaxial and abaxial leaf surfaces was performed. The microscopic measurements were carried out using a eyepiece-micrometer on microscope XSP-146TR. The obtained data were statistically processed with the program Statistica 6 on P ≤0.05 confi dence level. The pictures were taken by the digital camera Canon Power Shot A630. Results and discussions According to the complex researches the development of N. gigantea in greenhouse conditions continues during the last 8-10 years. It takes 3-4 years of development from sprouting seeds to fl owering plants. After that a phase of fl owering and fruit bearing begins that lasts for 5-6 months. For the next 2-3 years the plant continues its fl owering and bearing fruit. During the next two years the plant continues its fl owering but less abundantly. It was established that the fl ower of N. gigantea isn’t airhaic, the existence in its structure of platens, on which the sepals, petals, anthers and a pistil are accommodated, proves that fact. N. gigantea is included to a tuberous biomorphological structure. It was established, that the leaves of N. gigantea plant have specifi c anatomical features. Except an expressed aerenhim with single asterosclereids and hydropots in abaxial surfaces, the existence of large intercellular spaces fi lled with air in palisade mesophyll was founded. The heterophylia is observed on a morphological level annually after relative rest period. Conclusions According to the complex researches the development of N. gigantea in greenhouse conditions continues during the last 8-10 years. N. gigantea is included into tuberous biomorphological structure. It was established, that the leaves of the plants N. gigantea have specifi c anatomical features.