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Echinopsis
 

Echinopsis is a large genus of cacti native to South America, sometimes referred to as sea-urchin cactus or Easter lily cactus. The 128 species range from large and treelike types to small globose cacti. The name derives from echinos hedgehog or sea urchin, and opsis appearance, a reference to these plants' dense coverings of spines.

Echinopsis is distinguished from Echinocactus by the length of the flower tube, from Cereus by the form and size of their stems, and from both in the position on the stem occupied by the flowers. They are remarkable for the great size, length of tube, and beauty of their flowers, which, borne upon generally small and dumpy stems, appear much larger and more attractive than would be expected.

Distribution

The distribution of Echinopsis is similar to that of Echinocactus, species being found only in South America ( Argentina, Chile, Bolivia, Peru, Brazil, Ecuador, Paraguay and Uruguay ). They grow only in situations where the soil is sandy or gravelly, or on the sides of hills in the crevices of rocks.

Cultivation

The growing and resting seasons for Echinopsis are the same as for Echinocactus. Research by J. Smith (former Curator at the Royal Botanic Gardens, Kew) showed that species like the Chilean Echinopsis cristata and its Mexican relatives thrive if potted in light loam, with a little leaf mould and a few nodules of limestone. The limestone keeps the soil open; it is important that the soil should be well drained. In winter, water must be given very sparingly, and the atmosphere should be dry; the temperature need not exceed 10°C during the night, and in very cold weather it may be allowed to fall to 5°C, provided a higher temperature of 14°C is maintained during the day. In spring, the plants should receive the full influence of the increasing warmth of the sun; and during hot weather, they will be benefited by frequent spraying overhead, which should be done in the evening. The soil should never be saturated, as the soft fibrous roots will rot if kept wet for any length of time.

None of the species need to be grafted to grow freely and remain healthy, as the stems are all robust enough and of sufficient size to take care of themselves. The only danger is in keeping the plants too moist in winter, for although a little water now and again keeps the stems fresh and green, it deprives them of that rest which is essential to the development of their large, beautiful flowers in summer.

Taxonomy changes

Studies in the 1970s and 1980s resulted in several formerly separate genera being absorbed into Echinopsis: Some have proposed merging Rebutia as well.

The taxonomic changes have been criticised by K. Trout, in particular the inclusion of the genus Trichocereus, and the formation of a huge, complex new genus without an acompanying monograph. Some problems also arose due to namespace collision when this merger was made. Most notably, there had previously existed both Echinopsis bridgesii and Trichocereus bridgesii, which are very different plants. Echinopsis bridgesii is a short clumping cactus, whereas Trichocereus bridgesii is a tall columnar cactus similar to E. (or T.) pachanoi. Under the new classification, Trichocereus bridgesii is known as Echinopsis lageniformis. It should be pointed out that many people, still use the old Trichocereus classification, especially in ethnobotanical writings.

Species

Note: some of the species listed below may be synonymous, or subspecies or varieties of another.

Many hybrids exist, mostly between similar species but also between more distinct ones, such as the cross between E. pachanoi and E. eyriesii which was sold under the name "Trichopsis pachaniesii" by Sacred Succulents.

References

  • Edward F. Anderson, The Cactus Family (Timber Press, 2001) ISBN 0-88192-498-9, pp. 255-286
  • K. Trout, Trout's Notes on San Pedro & related Trichocereus species (Sacred Cacti 3rd ed. Part B) (Moksha Press, 2005) ISBN 0-9770876-0-3

External links

Cacti

Echinopsis | Echinopsis | Trichocereus | Echinopsis

 

This article is licensed under the GNU Free Documentation License. It uses material from the "Echinopsis".

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