Annona glabra, known as pond-apple, alligator-apple, swamp-apple, corkwood, and monkey-apple, is a tropical fruit tree in the family Annonaceae. Related species include cherimoya (A. cherimola) and soursop (A. muricata). It is native to southern Florida in the United States (including the Everglades), the Caribbean, Mexico, Central and South America, West Africa, and South Asia (Sri Lanka); it is an aggressive invader in the Pacific region.
A. glabra grows in swamps and tolerates saltwater; it cannot grow in dry soil. The trees reach a height of 15 m. They have thin, gray trunks, often buttressed at the base. Leaves, which are late deciduous, are ovate to oblong with an acute tip, 8–15 cm long and 4–6 cm wide. Flowers are solitary, 2–3 cm across, white to light yellow, with a rose-colored patch at each sepal base. Fruits are oblong to spherical, 7–15 cm long and up to 9 cm diameter (Wikipedia 2011).
Fruits disperse by floating on water. A. glabra appears to have naturally colonized West Africa from seeds transported on water from tropical America (Csurshes and Edwards 1998, ISSG 2011).
Pond-apple fruits are eaten by many animal species: the common name alligator-apple is said to come from the fact that American alligators eat the fruit. The fruit has pungent to aromatic flesh, which is edible for humans, and can be made into jam. Some people consider the flavor agreeable, while others have characterized it as “insipid” or “scarcely desirable” (FNA 2011, FOC 2011). The flavor and texture are considered inferior to the related cherimoya and soursop, and the fruit has never attained popular use. However, a recent study (Cochrane et al. 2008) suggests that an extract from pond-apple seeds contains anticancer compounds that could be used pharmaceutically.
A. glabra is used as a hardy rootstock for grafts of more commercially desirable related fruits, such as soursop and sugar-apple (A. squamosa). Other than this, it is not cultivated widely.
Through its introduction as a rootstock, however, A. glabra has escaped cultivation and become weedy or invasive in Pacific countries including Fiji, French Polynesia, Vietnam, and Australia (PIER 2011). The Global Invasive Species Database describes it as “a highly invasive woody weed that threatens wetland and riparian ecosystems of wet tropics, world heritage areas and beyond.” (ISSG 2011). It can invade fresh, brackish and saltwater areas and its thickets are capable of replacing whole ecosystems. Its seed is primarily dispersed by water, especially during floods. Disturbed flood-prone ecosystems are most at risk from pond apple invasion, particularly mangroves, melaleuca woodlands, riparian areas, drainage lines, coastal dunes and islands (Australian Government 2003). In estuaries and mangrove swamps, it can outcompete grasses and sedges, inhibit germination of Melaleuca species, and alter fire regimes (ISSG 2011).
It is categorized as a Class 2 weed in Australia, which indicates that it has spread over substantial areas of Australia (particularly in Queensland), and has serious impacts that must be controlled (Queensland 2007). Its sale in Australia for any purpose is prohibited.
- Australian Government. 2003. Weeds of National Significance—Weed management guide: Pond apple (Annona glabra). Retrieved 31 October 2011 from http://www.weeds.gov.au/publications/guidelines/wons/pubs/a-glabra.pdf’> http://www.weeds.gov.au/publications/guidelines/wons/pubs/a-glabra.pdf,
- Cochrane, C.B., P.K. Nair, S.J. Melnick, A.P. Resek, C. Ramachandran. 2008. Anticancer effects of Annona glabra plant extracts in human leukemia cell lines. Anticancer Research 28 (2A): 965–71.
- Csurches, S., and R. Edwards. 1998. Potential environmental weeds in Australia. Queensland Department of Natural Resources. Biodiversity Group, Environment Australia. P. 139. Retrieved 1 November 2011 from http://www.weeds.gov.au/publications/books/pubs/potential.pdf’> http://www.weeds.gov.au/publications/books/pubs/potential.pdf.
- FNA. 2011. Annona glabra Linnaeus. Flora of North America 3: 1753. Retrieved 31 October 2011 from http://www.efloras.org/florataxon.aspx?flora_id=1&taxon_id=200008506’> http://www.efloras.org/florataxon.aspx?flora_id=1&taxon_id=200008506
- FOC. 2011. Annona glabra Linnaeus. Flora of China 19: 712. Retrieved 31 October 2011 from http://www.efloras.org/florataxon.aspx?flora_id=2&taxon_id=200008506.
- ISSG. 2011. Annona glabra (tree). Global Invasive Species Database, Invasive Species Specialist Group, International Union for the Conservation of Nature. Retrieved 31 October 2011 from http://www.issg.org/database/species/ecology.asp?si=187&fr=1&sts=sss&lang=EN’>http://www.issg.org/database/species/ecology.asp?si=187&fr=1&sts=sss&lang=EN.
- PIER. 2011. Annona glabra. US Forest Service, Pacific Island Ecosystems at Risk (PIER). Online resource accessed 1 November 2011 at http://www.hear.org/pier/species/annona_glabra.htm.
- Queensland. 2011. Fact sheet: Pond apple (Annona glabra). Queensland Government, Department of Primary Industries and Fisheries, Land Protection (Invasive Plants and Animals). Retrieved 1 November 2011 from http://www.dpi.qld.gov.au/documents/Biosecurity_EnvironmentalPests/IPA-Pond-Apple-PP58.pdf>http://www.dpi.qld.gov.au/documents/Biosecurity_EnvironmentalPests/IPA-Pond-Apple-PP58.pdf.
- Wikipedia. 2011. "Annona glabra." Wikipedia, The Free Encyclopedia. 2 Jul 2011, 17:34 UTC. 17 Oct 2011. http://eol.org/pages/1054891/details#wikipedia.