The spirits that enliven the element of water are called undines. 

Image by Marie Laure Viriot

Once the plant has grown upwards, once it has left the domain of the gnomes and has passed out of the sphere of the moist-earthly element into the sphere of the moist-airy, the plant develops what comes to outer physical formation in the leaves. But in all that is now active in the leaves other beings are at work, water-spirits, elemental spirits of the watery element, to which an earlier instinctive clairvoyance gave among others the name of undines. Just as we find the roots busied about, woven-about by the gnome-beings in the vicinity of the ground, and observe with pleasure the upward-striving direction which they give, we now see these water-beings, these elemental beings of the water, these undines in their connection with the leaves."

Rudolf Steiner, The Plant-World and the Elemental Nature-Spirits, Lecture VII