Speaking again from the practical viewpoint property is of three kinds: Realty, personalty and mixed. Realty may be defined as the land and buildings thereon and anything permanently affixed to the land or the building. Personalty on the other hand is anything which does not fit within the definition of realty. For example, a watch, chairs, rugs and cultivated flower plants are personalty, while trees, buildings, furnace and plumbing as well as the land to which they are affixed are usually realty. Mixed property is of little importance, being such as may be alternately or interchangeably realty or personalty, e.g., a key in the door is an integral part of the building, hence realty; that same key found on the street is merely personalty. For practical purposes realty is often, though incorrectly, termed real property and personalty, personal property.