Thursday, January 12, 2012

Plant Profile: Opuntia stricta (Shell Mound Pricklypear)

Figure 1. Opuntia stricta, Jacksonville University. Photo credit: J. Larsen.
This post is one of a series from Botany professor Nisse Goldberg's students at Jacksonville University. Student authors: Jenell Larsen, Brooke Comans, and Trey Collins.

Classification:

Kingdom: Plantae
Phylum: Magnoliophyta
Class: Magnoliopsida
Order: Caryophyllidae
Family: Cactaceae
Genus: Opuntia
Species: Opuntia stricta

Also known as the erect pricklypear, the shell mound pricklypear is a cactus that grows on shell mounds, coastal hammocks, and dunes. The erect pricklypear is found in the southeast and coastal states of Florida, Alabama, Mississippi, Georgia, Texas, and South Carolina. It prefers sandy, well-drained soil. A long-lived plant, the shell mound pricklypear’s first flowers appear when the plant is three years old. 

The erect pricklypear can be identified by flat green segments that are not the leaves but the stems, which can measure up to 30 cm. It also has eyes that contain 0-11 spikes. The eyes of a cactus are called areola; areolas are the structures that spikes grow out of and the spikes are actually modified leaves. The areolas can grow roots when separated from their mother plant, which remain viable for months after detachment.

The bright yellow flowers bloom from February to July and are insect pollinated (Figure 1). Interestingly, ants can share a mutualistic relationship with Opuntia strica. The pricklypear provides the ants with nectar and the ants provide protection against herbivores. Mammals and birds eat the succulent, barrel-shaped fruits and are responsible for dispersing the seeds. Once deposited, the seeds can remain viable for as long as ten years.

Not only do animals find these fruits tasty, but so do humans. Pricklypear fruits, commonly called tunas, are sold fresh, canned or dried. They can be used in desserts, juices, jellies, spreads and shakes. In addition, they have many health benefits. Pricklypear fruits are used for their anti-inflammatory properties. They can also be used to lower sugar intake for type two diabetics and are found in laxatives and high cholesterol medications. The fruits may even aid in reducing the symptoms of alcohol hangovers!

Although Opuntia stricta is native to the state of Florida, it is invasive in other parts of the world, particularly in Australia. It is considered the oldest weed as it came to Australia on the first fleet. It was originally planted as a hedge to fence in cattle and also used for ornamental purposes. Used as a biological control, larvae of the Argentine cactus moth were successful in controlling populations of the cactus. In the United States, this moth is an invasive species and is threatening our erect pricklypear.

If you would like to have one in your garden, please visit the following link for vendors:
http://www.floridanativenurseries.org/plants/detail/opuntia-stricta

Bibliography

1. Plants database. (n.d.). Retrieved from http://plants.usda.gov/java/ClassificationServlet?source=profile&symbol=OPST2&display=31
2. Cactus. (n.d.). Retrieved from http://www.indoorflowers.net/cactus 3. Pickering. (n.d.). Opuntia stricta - erect pricklypear -- discover life. Retrieved from http://www.discoverlife.org/mp/20q?act=x_ant&path=Plantae/Dicotyledoneae/Cactaceae/Opuntia/stricta&name=Opuntiastricta&authority=(Haw.)Haw.&common_name=Erectpricklypear
4. Nature notes. (n.d.). Retrieved from http://www.friendsofbarefootbeach.org/FOBB/NatureNotes/NatureNotes-pricklypearcactus.pdf
5. Dee. (n.d.). Common prickly pear (opuntia stricta). Retrieved from http://www.esc.nsw.gov.au/weeds/Sheets/shrubs/SPricklypear.htm
6. Opuntia stricta in flora of north america @ efloras.org. (n.d.). Retrieved from http://efloras.org/florataxon.aspx?flora_id=1&taxon_id=242415190
7. Bartomeu. (n.d.). strength of invasive plant. Retrieved from http://www.uab.es/PDF/PDF_1212962705656_en.pdf
8. Robbins, Miller EX. (1970). An error occurred setting your user cookie. Retrieved from http://www.bioone.org/doi/pdf/10.1653/024.092.0231
9. Supple. (2011, November 10). nopal : Information on uses, dosage & side effects on healthline.com. Retrieved from http://www.healthline.com/natstandardcontent/nopal
10. Opuntia stricta (shrub). (2010, June 12). Retrieved from http://www.issg.org/database/species/ecology.asp?fr=1&si=104
11. Argentine cactus moth (cactoblastis cactorum). (n.d.). Retrieved from http://www.desertmuseum.org/invaders/invaders_cactusmoth.php



Also see blog post Edible Native Recovers from the Frost

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