The best thing about mistletoe, you may have thought, is that you can get a holiday kiss under it. But mistletoe is vital to the ecosystems it lives in.

Mistletoes are surprisingly diverse. There are over 1,000 species living on every continent but Antarctica and in every environment, from forest to desert.

They’re all parasites that grow on grasses, ferns and, most famously, trees. They attach with a haustorium, sort of a root that pierces the plant’s exterior to tap into its xylem to draw water and nutrients.

Most are evergreen, conducting photosynthesis to produce sugars. Most also produce flowers, which are full of sugary nectar, a high-energy food for bees and butterflies.

And most produce berries, which feed many species of birds—for some, it’s their only winter food. Some larger animals like possums, porcupines, deer and rhinos eat the mistletoe itself.

And its leaf litter is concentrated with nutrients stolen from host trees to enrich the forest soil.

Mistletoe is so essential that scientists have found that removing it from some forests reduces bird species by 25%.

While mistletoe is poisonous to humans, Native Americans used small doses to treat aches, epilepsy, and high blood pressure. And modern medicine is experimenting with it as therapy in cancer treatment.

Whether or not you get a kiss under it, mistletoe is still a plant to love.