Origin and Habitat: Bolivia, Argentina, Uruguay, and Paraguay

• Echinopsis multiplex (Pfeiff.) Zucc. ex Pfeiff. & Otto
• Cereus multiplex Pfeiff.
• Echinonyctanthus multiplex Lem.

• Echinopsis oxygona (Link) Zucc. ex Pfeiff.
• Cereus oxygonus (Link) Otto
• Echinocactus oxygonus Link
• Echinonyctanthus oxygonus (Link) Lem.
• Echinopsis multiplex (Pfeiff.) Zucc. ex Pfeiff. & Otto
• Cereus multiplex Pfeiff.
• Echinonyctanthus multiplex Lem.
• Echinopsis paraguayensis Mundt ex F.Ritter
• Echinopsis schwantesii Frič

• Echinopsis oxygona f. monstruosa hort.
• Cereus multiplex var. monstrosus Pfeiff.
• Echinopsis multiplex var. monstrosa Gürke

Description: Echinopsis multiplexSN|8380]]SN|8380]] is closely related to Echinopsis oxygonaSN|8376]]SN|8376]] and may not be easily distinct from the latter, but flower-tube more enlarged above and its scales distant, large. Echinopsis oxygonaSN|8376]]SN|8376]] is quite variable and has received numerous unnecessary names of no botanical value, representing no more than local phenotypes:Echinopsis multiplexSN|8380]]SN|8380]] is one of them, but it still has a value for a collector because they identify plants with particular characters.
In collections of cacti, plants apparently intermediate in character are frequently found, as well as many hybrids. This plant is common in cultivation.
Habit: These cacti grow rapidly and may simple or most often form big clumps up to 60 cm in diameter.
Stem: The stems is globose, globose to elongate, eventually short cylindrical to somewhat clavate, rounded or depressed at apex, clustering from near the base, green passing to greyish green or somewhat glaucous, (5-)10-15(-25) cm in diameter 15-30 cm high.
Ribs: 12-15, straight, broad at base, rounded on back, acute, slightly undulate.
Areoles: Large, filled with short white wool, about 1 cm apart.
Spines: 0.5 to 2.5 cm long subulate and stout, hard, blackish, yellowish-brown, brown, or horn coloured with darker tips, spreading and more or less curved.
Radial spines: The areoles have 13-15 radial spines, ascending, 2 cm long.
Central spines: 1-5, sometimes absent, thick, needle-like, eventually 20-45 mm long.
Flowers: Usually from areoles halfway up the side of the plant, white, pink, pale red to lavender, funnel-shaped, fragrant with long tubes 15-20(-30) cm long, 5-10 cm in diameter, its tube distinctly enlarged above, its scales large, distinct. Inner perianth-segments broad, rose-colored, acuminate. Stamens and style much shorter than perianth-segments, but exserted beyond the throat. Stigma-lobes white, slender, 6 or 7.Old plant may have dozen of stunning flowers open at a time.
Blooming season: This species blooms from late spring to all summer long. The flower last only one day in full beauty, they open at evening and start to wither the next afternoon on hot days. On cool days they will last longer.
Fruit: Fruits green, to 4 cm long and 2 cm in diameter.
Remarks: This plant has been widely crossed with other species of Echinopsis and the number of cultivars seems unending. The flowers are lovely and are available in an assortment of bright colours ranging from magenta, red, orange, to yellow, and much sought-after by Cactophiles everywhere.

Notes: The cacti that love hawkmoths pollination.
This species is a sphingophilous plant (pollinated by hawkmoths) and is recognized for the white trumpet nocturnal flowers. Many species of cacti utilize hawkmoth pollination and depend on hawkmoths for successful seed production. (e.g., Echinopsis multiplexSN|8380]]SN|8380]], Acanthocereus tetragonusSN|4324]]SN|4324]], and Hylocereus hundatus) whereas others are more tubular (species of Selenicereus and Stenocereus erucaSN|7988]]SN|7988]]). It is unlikely that only one moth species is pollinating only one flower species, so there will be mixed pollen grains of many species on the insect. That notwithstanding, hawkmoths are credited as fairly reliable long-distance cross-pollinators because they are able to carry even small amounts of pollen to isolated, self-incompatible plants in tropical areas to produce fruits with viable seeds.
Sphingophilous flowers are largely unused by other classes of pollinators. These nocturnal flowers are unavailable to day-active pollinators until the next morning, and, in fact, bees of various types sometimes arrive during morning hours to accomplish an even higher level of pollination success.

Bibliography: Major references and further lectures
1) Edward Anderson “The Cactus family” Timber Press, Incorporated, 2001
2) 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
3) David R Hunt; Nigel P Taylor; Graham Charles; International Cactaceae Systematics Group. "The New Cactus Lexicon" dh books, 2006
4) Friedrich Ritter "Kakteen in Südamerika: Ergebnisse meiner 20jährigen" Volume 2, Argentinien/Bolivien, Volume 2 Selbstverlag, 1980
5) Curt Backeberg “Die Cactaceae: Handbuch der Kakteenkunde,” Volume 2 G. Fischer, 1959
6) Curt Backeberg: “Descriptiones Cactearum Novarum.” 1957
7) Walter Rausch “Lobivia: The Day Flowering Echinopsidinae from a Geographical Distribution Point of View” Volumes 1-3 R. Herzig, 1975
8) Urs Eggli, Leonard E. Newton “Etymological Dictionary of Succulent Plant Names.” Springer, Berlin/Heidelberg 2010.
9) N. L. Britton and J. N. Rose “The 'Cactaceae', Descriptions and Illustrations of Plants of the 'Cactus' Family” volume 3 Carnegie Institution, 1922.
10) John Borg "Cacti: a gardener's handbook for their identification and cultivation" Blandford P., 1970
11) H. Peter Loewer “The Evening Garden” Macmillan Pub., 1993
12) Vera Higgins “Cactus Growing for Beginners” Blandford Press, 1964
13) Willy Cullmann, Erich Götz (Dozent Dr.), Gerhard Gröner “The encyclopedia of cacti” Timber Press, 1987
14) Haustein, Erik. “Der Kosmos-Kakteenführer.” Kosmos / Gesellschaft der Naturfreunde., Stuttgart, 1983
15) Larocca, J., Machado, M., Kiesling, R., Oakley, L. & Pin, A. 2013. Echinopsis oxygona. In: IUCN 2013. “IUCN Red List of Threatened Species.” Version 2013.2. <www.iucnredlist.org>. Downloaded on 08 May 2014.

Cultivation and Propagation: The Easter Lily cactus is a summer grower species that offers no cultivation difficulties. Water regularly in summer (but do not overwater ) needs good drainage and very porous soil, keep rather dry in winter. Feed with a high potassium fertilizer in summer. It is quite frost resistant if kept dry (hardy to -7° C). Need a bright exposure, full sun or half shade in summer.
Propagation: Direct sow after last frost, offsets.