The New Student's Reference Work/Ivy
Ivy, a name applied to a variety of woody plants which have the habit of climbing by means of sucker-like discs, so that they can attach themselves to walls and other vertical surfaces. This habit makes the plants valuable in connection with the covering and ornamenting of walls, houses, churches etc. The common European ivy is Hedera helix, which belongs to the aralia family. It is evergreen, with entire or three-to-five lobed leaves and usually black berries. It is an exeeedingly variable species, and more than 60 species have been cultivated in European gardens. The American ivy or woodbine is a species of Ampelopsis, a genus which belongs to the grape family. It is a much more rapid-growing vine than the English ivy, and its leaves color bright scarlet in autumn. About 20 species are known in North America and Asia, the common one in the United States being A. quinquefolia, often called the Virginia creeper. Japan ivy or Boston ivy is also a species of Ampelopsis (A. tricuspidata), being especially useful, since it covers walls very densely and its glossy leaves stand dust and smoke well. This probably is the favorite among the hardy vines in cities. The name of poison ivy is applied to various poisonous species of Rhus (R. toxicodendron, also known as poison oak, being the chief one), a genus which belongs to the cashew family.