Annona is a genus, or related group, in the pawpaw and sugar apple family called Annonaceae. Its name originates from the word anón which is a Hispaniola word meaning "fruit." The genus has more than 100 species of flowering plants, seven of which are grown commercially for the use of the plants fruits, and some of the other species are used in traditional medicine.
The Annona squamosa is commonly known as the sugar apple or custard apple. It is indigenous to the Amazon rain forest and can grow up to 20 feet (6 m) tall. The fruits of the tree have a purple skin that is knobby and has a very sweet flesh inside that can be eaten raw. The seeds inside the fruit are black and poisonous. The bark of the tree and the leaves contains annonaine, which is an alkaloid and is used as a cold remedy in tropical parts of the Americas.
Annona muricata is also known as soursop, and it is a small tree that grows to a height of about 25 feet (8 m). The tree needs a lot of warmth and water and will die if temperatures drop below 32 degrees Fahrenheit (0 degrees Celsius). The fruit on the tree, the soursop, is known around the world and has a white flesh with up to 100 small black seeds. The soursop is often made into ice creams and sorbets, but the fiber-free soursops can be eaten raw. Extracts from the Annona muricata are known to inhibit the herpes simplex virus, which is more commonly known as the cold sore virus.
Also known as the monkey apple or alligator apple, Annona glabra is native to Florida and the West Indies. It can grow to a height of 50 feet (16 m) and has a thin trunk that is gray in color, and this species has leaves that are oblong in shape and measure 3 inches (8 cm) in length. The fruit from the tree is apple-size and is edible, being commonly used in jams, though the taste of the soursop is preferred by most people. The pond apple is considered one of the worst invasive weeds in Australia, because the trees grow closely together and stop any other plants from being able to grow in the area. They are able to grow in flooded areas, and when the fruits fall, they are carried off on the water and invade other areas along creeks, thus affecting other farming areas.