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Origin and Habitat: Northern Argentina. It is also present in Brazil (Mato Grosso do Sul), southern lowland Bolivia, Uruguay, and Paraguay.
Type locality: Territory of the Chaco, Argentina.
Habitat and ecology. Opuntia anacantha var. retrorsa is often found on dry dune in the Chaco regions but also in the humid-Subhumid (or Eastern) Chaco woodland. Cacti such as: Cleistocactus baumannii, Echinopsis rhodotricha, Harrisia balansae, Harrisia tortuosa, and Stetsonia coryne are an important feature of these woodlands. At field level common herbaceous species are Aechmea distachantha, Dyckia ferox and various grasses.
- Opuntia anacantha var. retrorsa (Speg.) R.Kiesling
Opuntia anacantha var. retrorsa (Speg.) R.Kiesling
Candollea 53: 475. 1998
- Opuntia anacantha var. retrorsa (Speg.) R.Kiesling
- Opuntia platynoda Griffiths
Opuntia anacantha Speg.
Bull. Mus. Hist. Nat. (Paris) 10: 391 1904
- Opuntia anacantha Speg.
- Platyopuntia kiska-loro (Speg.) F.Ritter
- Opuntia bispinosa Backeb.
- Opuntia canina Speg.
- Opuntia grosseana F.A.C.Weber
- Opuntia roborensis Cárdenas
- Opuntia vitelliniflora (F.Ritter) P.J.Braun & Esteves
- Platyopuntia vitelliniflora F.Ritter
Opuntia anacantha var. kiska-loro (Speg.) R.Kiesling
Candollea 53: 475. 1998
Opuntia anacantha var. utkilio (Speg.) R.Kiesling
Candollea 53: 476. 1998
SPANISH (Español): tuna
Description: Opuntia anacantha var. retrorsa, (Opuntia retrorsa), is a jointed shrubby cactus, usually decumbent and rooting along the under surface, sometimes ascending and clambering, forming low clumps to 60 cm high and 2.5 m wide. The joints are typically with sharp spines turned backward and has violet stripes downwards from the areoles. It is one of the morphological or local forms of the very variable Opuntia anacantha (typically unarmed), and the two plants are not readily distinguishable, if not for the presence of spines. More likely they are one and the same species. Opuntia anacantha presents a large morphological variability and has a large distribution area.
Derivation of specific name: 'retrorsa' [Latin retrorsus, from retroversus: retro- + versus, past participle of vertere, to turn] for the spines that are decurved, turned backward or curved downward
Stems: Prostrate, intricately branched, creeping, rooting at the nodes; joints linear-lanceolate, more or less attenuate at each end, flattened.
Areoles: Smewhat prominent, each subtended by a long, dull purplish blotch.
Spines: 1 to 6, reflexed, white below, with pinkish tips, about 3–4cm long.
Flowers: The flowers are diurnal, 5-5 cm long, 4-4,5 cm broad, yellow, solitary, open and shallow, not displaying a floral tube, but presenting a globose pericarpel, and contain about 160-260
stamens and about 70-85 ovules. Floral morphology suggests that bees are the pollinators.
Fruit: About 20-40 mm in length, and 4-4.5 g weight, globose, indehiscent, covered with glochideos red to violet-purple on the outside, light rose on the inside and have 32-37 seeds.
Seeds: 2 to 3,7 mm in length, 1.8-2 mm in diameter and weight ca. 95-105 mg, brown, embedded in a transparent pulp, and somewhat villous. Small mammals can act as potential dispersers of this cactus.
Similar species: Opuntia anacantha var. retrorsa, occurring in Argentina, is quite similar to the Bolivian Opuntia fuscolineata, but O. fuscolineata has dark brown stripes downwards from the areoles (not violet), fewer and shorter spines, which are only 2.5 cm long, and in older areoles only additionally 1–3 minor spines about 1 cm long. It has also smaller flowers (about 3 cm in diameter). There is another species with purplish stripes below the areoles in the adjacent region: Opuntia paraguayensis. However, the stem segments in this opuntia are much wider (5–8.5cm), spines are usually absent (occasionally one yellowish), and the flowers are much bigger (to 8 cm) and orange.
Subspecies, varieties, forms and cultivars of plants belonging to the Opuntia anacantha group
- Opuntia anacantha Speg.: (var. anacantha) has dark green stem segments usually spineless and yellow flowers. Distribution: Southern Gran Chaco region of Argentina.
- Opuntia anacantha var. kiska-loro (Speg.) R.Kiesling: has light green stem segments and orange flowers. Distribution: far north of Argentina into Bolivia.
- Opuntia anacantha var. retrorsa (Speg.) R.Kiesling: has light green stem segments with sharp spines turned backward and has violet stripes downwards from the areoles. Flowers are yellow. Distribution: grassland in southern part of the range, Argentina.
- Opuntia anacantha var. utkilio (Speg.) R.Kiesling: has elliptical, green stem segments and yellow flowers. Distribution: near Tucuman, Argentina.
Bibliography: Major references and further lectures
1) N. L. Britton, J. N. Rose: “The Cactaceae. Descriptions and Illustrations of Plants of the Cactus Family.” Vol I, The Carnegie Institution of Washington, Washington 1919
2) Felix Faustino Outes, Fernando Lahille, Museo Argentino de Ciencias Naturales "Anales del Museo Nacional de Ciencias NaturalesBernardino Rivadavia" Juan A. Alsina, 1905
3) Gomes, Vanessa G.N.; Araújo, Andréa C. “Cacti species from the Brazilian Chaco: floral and fruit traits” in: Gaia Scientia v. 9, n. 2 (2015)
4) Walter Starmühler & Walter Mucher sen. “Two new Opuntia species (Cactaceae) from Bolivia and Argentina” in: Wulfenia - Mitteilungen des Kärntner Botanikzentrums Klagenfurt 12 (2005): 57–63
5) Peter Martin Rhind “Plant Formations in the Chacoan and South Andean Yungas BioProvince” <http://terrestrial-biozones.net/Neotropic%20Vegetation/Chacoan%20Vegetation.pdf>
6) Anderson, E. F. “The cactus family” 2001
7) Hunt, D., Taylor, N. and Charles, G. “The New Cactus Lexicon.” dh Books, Milborne Port, UK. 2006
Flowers on an almost completely dehydrated plant. Sometimes Opuntia retrorsa begins to bloom in November even without rain. Photo by: Alexander Arzberger
The gallery now contains thousands of pictures, however it is possible to do even more. We are, of course, seeking photos of species not yet shown in the gallery but not only that, we are also looking for better pictures than those already present. Read More...
Cultivation and Propagation: Opuntia anacantha var. retrorsa, (Opuntia retrorsa) is a a much decorative cactus not very common in cultivation. It is a summer grower species that offers no cultivation difficulties.
Soil: Use a very a particularly draining substratum, as it is sensitive to rottenness when in presence of humidity and low temperatures and let the soil dry out between waterings, since it's natural habitat is in sandy or gravelly, well draining soils.
Repotting: Repot in the spring, when their roots become cramped. Generally, they should be repotted every other year in order to provide fresh soil. After repotting, do not water for a week or more.
Water: In summer, during the vegetative period, it must be regularly watered, but allowing the substratum to completely dry up before irrigating again (but do not overwater ); in winter, it’s to be kept dry. Preferable not to water on overcast days, humid days or cold winter days.
Hardiness: It is a quite frost resistant cactus, hardy to -7° C. However in cultivation it is better not to expose it to temperatures lower than -0° C, even if in an aerated and protected location, in order to avoid the formation of anti-aesthetic spots on the epidermis. In presence of high atmospheric humidity avoid any frost as it is particularly sensitive to root rot. USDA Zone 7-10. It can handle extremely high temperatures in summer.
Exposure: Outside full sun or afternoon shade, inside needs bright light, and some direct sun.
Use: It is suitable for “desert” gardens, in association with other xerophytes. Where the open air cultivation is not possible due to the climate, it is to be cultivated in pot in order to shelter it in winter.
Warning: It is armed with treacherous spines that are extremely sharp. Handle it with caution, and keep it away from gangways and areas frequented by children and animals. Spines must be meticulously removed with tweezers.
Propagation: Stem division. Prickly pear pads root easily and grow rapidly when placed in loose, well-draining soil.
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