Science Fair Project Encyclopedia
- This page refers to the true pawpaws in the genus Asimina. The name pawpaw is also often applied to the unrelated tropical fruit papaya (Carica papaya).
Pawpaw (Asimina) is a genus of eight or nine species of small trees with large leaves and fruit, native to southeastern North America. The genus includes the largest edible fruit native to North America. They are understorey trees of deep fertile bottomland soils. The name, also spelled paw paw, paw-paw, and papaw, probably derives from the Spanish papaya, perhaps due to the superficial similarity of their fruit. Pawpaw is in the same family Annonaceae as the custard-apple, cherimoya, sweetsop , and soursop, and it is the only member of that family not confined to the tropics.
The pawpaws are shrubs or small trees, reaching heights of 2-12 m tall. The leaves are alternate, simple ovate, entire, 20-35 cm long and 10-15 cm broad. The northern, cold-tolerant Common Pawpaw is deciduous, while the southern species are often evergreen. The unpleasant–smelling flowers are produced singly or in clusters of up to eight together; they are large, 4-6 cm across, perfect, with six sepals and petals (three large outer petals, three smaller inner petals). The petal color varies from white to purple or red-brown. Pollinated by scavenging carrion flies and beetles, the weak scent of the flowers are insufficient in attracting many pollinators to the flowers, thus limiting fruit production.
The fruit is a large edible berry 5-16 cm long and 3-7 cm broad, weighing from 20-500 g, with numerous seeds; it is green when unripe, maturing to yellow or brown. It has a flavor somewhat similar to both banana and mango, varying significantly by cultivar, and has more protein than most fruits.
- Asimina angustifolia Raf. - Slimleaf Pawpaw. Florida, Georgia and Alabama.
- Asimina incana (W. Bartram) Exell - Woolly Pawpaw. Florida and Georgia.
- Asimina obovata (Willd.) Nash - Bigflower Pawpaw. Florida.
- Asimina parviflora (Michx.) Dunal - Smallflower Pawpaw. Southern states from Texas to Virginia.
- Asimina pygmea (W. Bartram) Dunal - Dwarf Pawpaw. Florida and Georgia.
- Asimina reticulata Shuttlw. ex Chapman - Netted Pawpaw. Florida and Georgia.
- Asimina tetramera Small - Fourpetal Pawpaw. Florida .
- Asimina triloba (L.) Dunal - Common Pawpaw. Extreme southern Ontario, Canada, and the eastern United States from New York west to southeast Nebraska, and south to northern Florida and eastern Texas.
Although it is a delicious and nutritious fruit, it has never been cultivated on the scale of apples and peaches, primarily because it does not store or ship well. It is also difficult to transplant due to its long taproot. Cultivars are propagated by chip budding or whip grafting.
In recent years the pawpaw has attracted renewed interest, particularly among organic growers, as a native fruit which has few pests, and which therefore requires little pesticide use for cultivation. The shipping and storage problem has largely been addressed by pulping the fruit and freezing the pulp.
The commercial growing and harvesting of pawpaws is strongest in southeast Ohio. The Ohio Pawpaw Growers' Association annually sponsors the Pawpaw Festival at Lake Snowden near Albany, Ohio. This group is also urging the Ohio state legislature to make the pawpaw the state fruit.
The flowers are self-incompatible, requiring cross pollination; at least two different varieties of the plant are needed as pollenizers. The flowers produce an odor similar to that of rotting meat to attract blowflies or carrion beetles for cross pollination. Lack of pollination is the most common cause of poor fruiting, and growers resort to hand pollination or to hanging chicken necks or other meat to attract pollinators.
This colonial tree has a strong tendency to form colonial thickets if left unchecked.
The earliest documentation of pawpaws is in the 1541 report of the de Soto expedition, who found Native Americans cultivating it east of the Mississippi River. The Lewis and Clark Expedition depended and sometimes subsisted on pawpaws during their travels. Chilled pawpaw fruit was a favorite dessert of George Washington.
A chemical in the fruit? is one of the most potent and least toxic anti-cancer agents currently known. Cultivars hope this will eventually lead to market demand from the pharmaceutical industry.
- USDA distribution of Pawpaw
- Pawpaw Information from Kentucky State University
- Asimina Genetic Resources
- Clark's September 18, 1806 journal entry about pawpaws
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