Opuntia is a genus in the cactus family, Cactaceae.
The most common culinary species is the Indian fig opuntia (O. ficus-indica). Most culinary uses of the term “prickly pear” refer to this species. Prickly pears are also known as tuna (fruit) or nopal (paddle, plural nopales) from the Nahuatl word nōpalli for the pads, or nostle, from the Nahuatl word nōchtli for the fruit; or paddle cactus
Prickly pears typically grow with flat, rounded cladodes (also called platyclades) armed with two kinds of spines; large, smooth, fixed spines and small, hairlike prickles called glochids, that easily penetrate skin and detach from the plant. Many types of prickly pears grow into dense, tangled structures.
Like all true cactus species, prickly pears are native only to the Americas, but they have been introduced to other parts of the globe. Prickly pear species are found in abundance in Mexico, especially in the central and western regions, and in the Caribbean islands (West Indies). In the United States, prickly pears are native to many areas of the arid Western United States, including the lower elevations of the Rocky Mountains, where species such as Opuntia phaeacantha and Opuntia polyacantha become dominant, and especially in the desert Southwest. Prickly pear cactus is also native to the dry sandhills and sand dunes of the East Coast from Florida to Connecticut/Long Island (Opuntia humifusa). Further north, Opuntia occurs in isolated areas from the southern Great Lakes to southern Ontario. O. humifusa is also a prominent feature of the flora at Illinois Beach State Park, in Winthrop Harbor, Illinois, north of Chicago, and of Indiana Dunes State Park southeast of Chicago.
In the Galapagos Islands, six different species are found: O. echios, O. galapageia, O. helleri, O. insularis, O. saxicola, and O. megasperma. These species are divided into 14 different varieties; most of these are confined to one or a few islands. For this reason, they have been described as “an excellent example of adaptive radiation”. On the whole, islands with tall, trunked varieties have giant tortoises, and islands lacking tortoises have low or prostrate forms of Opuntia.
The first introduction of prickly pears into Australia are ascribed to Governor Philip and the earliest colonists in 1788. Brought from Brazil to Sydney, prickly pear grew in Sydney, New South Wales, where they were rediscovered in a farmer’s garden in 1839. They appear to have spread from New South Wales and caused great ecological damage in the eastern states. They are also found in the Mediterranean region of Northern Africa, especially in Tunisia, where they grow all over the countryside, and arid southern Europe, especially on Malta, where they grow all over the islands, in the south-east of Spain, and can be found in enormous numbers in parts of South Africa, where it was introduced from South America.
Opuntia species are the most cold-tolerant of the lowland cacti, extending into western and southern Canada; one subspecies, O. fragilis var. fragilis, has been found growing along the Beatton River in central British Columbia, southwest of Cecil Lake. Prickly pears also produce a fruit, commonly eaten in Mexico, known as tuna; it also is used to make aguas frescas. The fruit can be red, wine-red, green, or yellow-orange.
Charles Darwin was the first to note that these cacti have thigmotactic anthers: when the anthers are touched, they curl over, depositing their pollen. This movement can be seen by gently poking the anthers of an open Opuntia flower. The same trait has evolved convergently in other cacti (e.g. Lophophora).
Tephrocactus is a small genus in the subfamily Opuntioideae which is endemic to Argentina. Like other members of this group, Tephrocactus does have glochids, however, they are uniquely sunken into the areoles in this genus. Spines may be long, dense and needle-like or thin and papery or absent. The stems grow in very distinct segments, but unlike the flat-pads found on the genus Opuntia, the segments of Tephrocactus are round. This can be either in short cylinders, egg shaped, or even spherical. These segments typically grow in a slightly zig-zagged stack. Flowers are white in most species or pinkish, sometimes yellow, and in one case red.
Some species in this genus are very popular in cultivation. Grown for their alien-looking stems and dramatic spines. Flowers are less common in cultivation as the segments often detach with the slightest touch. Plants that are only a couple segments high tend not to flower. As such, a flowering Tephrocactus is a special delight to the hobbyist.
The meanings of latin plant names on this page – from http://davesgarden.com/guides/botanary/
- aciculata [ass-sik-yoo-LAY-ta]
1. Needle-like; needle-shaped.
2. Marked with fine, irregular streaks.
- articulatus [ar-tik-oo-LAH-tus, ar-tik-yoo-LAH-tus]
Having joints, jointed.
- aurantiaca [aw-ran-ti-AYE-kuh]
- basilaris [bas-il-LAIR-iss, base-IL-ah-riss]
- ficus-indica [FY-kuss IN-dih-kuh, FY-kuss in-DEE-kuh]
Fig of India.
- helleri [HEL-ler-ee]
Named for Amos Arthur Heller, 20th century North American plant collector who discovered the species; also spelled hellerii.
- humifusa [hew-mih-FEW-suh, hum-ih-FEW-suh]
- inermis [IN-er-mis]
Not spiny, unarmed.
- insularis [in-soo-LAIR-is]
Pertaining to or growing on islands.
- leucotricha [loo-koh-TRY-kuh]
- macrocentra [mak-roh-SEN-truh]
- megasperma [meg-uh-SPER-muh]
- microdasys [my-kro-DAS-is]
Small and bushy.
- monacantha [mon-ah-KANTH-uh]
From the Greek monos (one, only) and akantha (thorn, spine).
- Opuntia [op-UN-shee-a, op-UN-tee-a]
Named after Opus (Greece), an area where other cactus-like plants were grown.
- ovata [oh-VAY-tuh]
Ovate in shape.
- phaeacantha [fay-uh-KANTH-uh]
From the Greek phaios (dusky, gray) and kantha (thorn), referring to the gray thorns.
- polyacantha [pol-lee-uh-KAN-tha]
- saxicola [saks-ee-KOH-luh]
- stricta [STRIK-tuh]
- Tephrocactus [tef-roh-KAK-tus]
From the Greek tephros (ash-colored) and cactus.