What are Hydathodes or Water Stomata?

These are structurally modified portions of leaf which are meant to send out excess amount of water in liquid form. They are are called Hydathodes or water stomata. The process of water secretion through them is called guttation. The process can be noticed early in the morning.  They are present usually at the rip or margins of leaves of those plants that growing in moist places.

Each hydathodes has a mass of loosely arranged cells with large intercellular spaces called epithem. This epithem lies above a vein ending and is connected with external atmosphere through a pore in the epidermis, known as water stomata. The guard cells here are small and devoid of chloroplasts. The hydathodes are always in the open condition. The mechanism of stomata opening and closing is absent here.