Emerald ferns are part of the Asparagus family (Asparagaceae). They are not 'true' ferns and are more closely related to the edible asparagus vegetable, hence why it is also referred to as an Asparagus fern. But some have said they belong to the Lily family (Liliaceae). This confusion possibly stems from the fact that some of the species now under the Asparagus family used to fall under a catch-all group in the Lily family.