The nine-leafed tooth is an evergreen or lively perennial aquatic plant native to East Asia. It forms dense tufts made up of thin elongated, flexible, green stems, which bear numerous compound leaves, made up of three elements, which are spread out so as to make the whole leaf seem roundish.
The whole plant can develop completely submerged, in this case it assumes a very light green color; if, on the other hand, it emerges from the water, it takes on a more intense and dark color. In spring it produces small inflorescences made up of white, inconspicuous flowers. These seedlings are often used also in aquariums; in this case they do not produce flowers, moreover, if kept at temperatures above 25-28 ° C they tend to produce very small leaflets and have a more elongated and less dense appearance.
For the best growth of the nine-leaf tooth, it is advisable to place it on the bottom or on the edges of an aquatic garden in a bright place, but not directly exposed to sunlight; generally the cardamine lyrata plants resist very well to the cold; sometimes the plants can suffer during very hot summers, to the point of drying up and going into vegetative rest, generally they reappear in autumn or during the following spring.
If the nine-leaf tooth is grown totally submerged, the coloring of its foliage is a light green color; instead, if the plants are placed outside the water, the foliage takes on a darker color.