Origin and Habitat: Argentina (La Rioja and Mendoza).
Altitude: 800 to 1250 meters.
Habitat: It grow on high-plains in different environments both in open areas and under shrubs.

• Tephrocactus aoracanthus var. paediophilus (A.Cast.) J.G.Lamb.
• Opuntia paediophila A.Cast.
• Tephrocactus paediophilus (A.Cast.) F.Ritter

• Tephrocactus aoracanthus (Lem.) Lem.
• Cereus ovatus Don
• Opuntia aoracantha Lem.
• Tephrocactus aoracanthus var. paediophilus (A.Cast.) J.G.Lamb.
• Opuntia paediophila A.Cast.
• Tephrocactus paediophilus (A.Cast.) F.Ritter
• Tephrocactus hossei Krainz & Gräser
• Opuntia hossei (Krainz & Gräser) G.D.Rowley
• Tephrocactus ovatus (Gill. ex Loudon) F.Ritter non Backeb.
• Cactus ovatus Gill. ex Loudon

Description: Tephrocactus aoracanthusSN|8453]]SN|8453]] var. paediophilus is an extraordinary variety that shows wonderful spines to as much as 30 cm long (the longest in the genus Tephrocactus). These spines are papery but still sharp enough to molest anything that gets near it! The spines are stiff and stick out to every thing that enter in contact with them, this way the stems segment spread around in the environment. Delicate alabaster white flowers are rarely produced.
Habit: Plants erect that will form clumps with some branching with age, 30-100 cm high and 1-3 metres in diameter, but usually couldn’t get very tall as segment kept falling apart.
Stem segments: Somewhat fragile (easily detached), ellipsoidal to ovoid, prominently tuberculate, 5-10 cm long and 4-8 cm in diameter, of a very characteristic pale grey or greys-green colour.
Tubercles: Moderately to strongly defined, forming a network of more or less regular spiralling lozenge in the epidermis.
Areoles: Small on top of a conical protuberance, as many as 60 per segment (but usually about 30) extending to the base. The basal areoles are spineless 2-3 mm in diameter, while the areolae in the upper two thirds of the segments are significantly larger (up to 6mm) and bear spines. The new areoles at first are filled with white hyaline wool (rarely brown at the the centre). In the centre of the areola there are stiff, yellowish brown glochids up to 5 mm long.
Spines: 7-8, stout, very unequal, erect or spreading in all directions, slightly flexible to papery, but still very sharp, often twisted and intertwined, reddish brown to black, round or slightly angled in cross section, up to 30 cm long.
Flowers: Large, white to light pink, 4-6 cm long by 5-8 cm in diameter; tepals broadly spatulate with a hard and brown mucro; pericarpels inverted cone-shaped up to 3 cm long and 2 cm in diameter, with many glochids and sometimes with spines up to 15 mm long on rims at the top of the pericarpel. The stamens are sensitive; filaments white; anthers yellow; style clavate white with up to 8 stigma lobes.
Fruits: Spherical to oval, up to 3 cm in diameter dehiscing irregularly, sometimes with persistent spines.

Bibliography: Major references and further lectures
1) James Cullen, Sabina G. Knees, H. Suzanne Cubey “The European Garden Flora Flowering Plants: A Manual for the Identification of Plants Cultivated in Europe, Both Out-of-Doors and Under Glass” Cambridge University Press, 11/Aug./2011
2) David Hunt, Nigel Taylor “The New Cactus Lexicon” DH Books, 2006
3) Edward F. Anderson “The Cactus Family” Timber Press, 2001

Cultivation and Propagation: It is easy to grow. The main growing period is spring. It might produce some new segments in the autumn too.
Hardiness: It is fairly cold resistant and hardy to -9°C depending on the clone.
Exposure: Need full sun, (with insufficient illumination stems and spines get thinner as a result of the lack of sun)
Soil requirements: It needs a very draining mineral substrate.
Water needs: Watering during the active growing season (spring and summer); this will encourage steady growt. But be careful with watering (rot sensitive). Keep dry during the winter rest.
Fertilization: Fertilize moderately during the growing seson with diluted high potassium fertilizer.
Propagation: Cuttings, or occasionally seeds. It suckers profusely and is very easy to grow by just knocking off one of the 'cones' and stuffing it in the ground.
Warning Handle with care! The little glochids at the base of these larger spines are quite a nuisance and the minimal touch may be fatal. It is best to use gloves to handle this plant.