Hoya is a genus of 200–300 species of tropical plants in the dogbane family, Apocynaceae. Most are native to several countries of Asia such as Philippines, India, Thailand, Malaysia, Vietnam, Bangladesh, Indonesia, Polynesia, New Guinea, and vast variety of species could also be found in Australia. Hoyas are evergreen perennial creepers or vines or rarely, shrubs. They often grow epiphytically on trees; some grow terrestrially, or occasionally in rocky areas. They climb by twining, and with the employment of adventitious roots. Larger species grow 1–18 m (3–59 ft), or more, with suitable support in trees. They have simple entire leaves, arranged in an opposite pattern, that are typically succulent. Leaves may exhibit a variety of forms, and may be smooth, felted or hairy; venation may be prominent or not, and many species have leaf surfaces flecked with irregular small silvery spots.