- An individual descending from crosses between two or more species. (This is a botanical definition that is also widely used in horticultural commerce.) While in the AHSwe may loosely refer to the results of our crosses as hybrids to distinguish them from the original species, they are more appropriately referred to as cultivars if registered, and seedlings if not registered.
- The first generation (F1) from crossing differing true-breeding parents to produce uniform non true-breeding offspring with hybrid vigour. This is a specialized plant breeding definition that does not apply to any registered daylilies. However, it does apply to many hybrid crops such as tomatoes and corn.