Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. Vincetoxicum is a genus of plant in family Apocynaceae. Although the species in Vincetoxicum have sometimes been included in Cynanchum, chemical and molecular evidence shows that Vincetoxicum is more closely related to Tylophora. The Apocynaceae or dogbane family is a family of flowering plants that includes trees, shrubs, herbs, and lianas. Many species are tall trees found in tropical rainforests, and most are from the tropics and subtropics, but some grow in tropical dry, xeric environments. There are also perennial herbs from temperate zones. Many of these plants have milky sap; and many species are poisonous if ingested. Some genera of Apocynaceae, such as Adenium however, have either clear and milky, latex sap, and others, such as Pachypodium, always have clear sap.