Generally, a botanic garden grows plants because of their scientific interest; a garden grows plants for their aesthetic appeal. This scientific interest can be at many levels; most importantly a botanic garden keeps a record of from where and when plants arrived in the garden and where they are growing. By keeping a wide range of species and cultivars, the collection can be used for reference - to help identify plants; education - illustrating an interesting fact about botany or the way in which a plant is important to people; conservation - we grow many rare and endangered species, not only from Ireland but from all over the world; science - the biology of many species is still poorly known and understood, and a number of new species have even been described from within the living collections at Glasnevin; horticultural - learning how to grow scarce or difficult plants is important for furthering our knowledge of plants; and lastly, we never forget that many plants are beautiful for their own sake, and the amenity value of the collections is always considered.