Origin and Habitat: New Mexico.

• Escobaria vivipara var. borealis n.n.
• Escobaria borealis (Engelm.) E. Lutz
• Mammillaria radiosa var. borealis Engelm.
• Mammillaria vivipara var. borealis

Description: Escobaria viviparaSN|10274]]SN|9953]] is a small solitary or clumping cactus, some varieties forming colonies of over 200 stems. This species is the most widespread, abundant and variable member of the genus.
Remarks: The “borealis” variety is a controversial name that has sunk into complete obscurity and considered by some authors synonymous with Escobaria viviparaSN|9953]]SN|9953]] var. neomexicana. Perhaps the name "borealis" (of the north) was originally intended for the strange very northern vivipara that have very open spination and look somewhat more like Escobaria missouriensisSN|9953]]SN|10274]], but this northern form never seem to have acquired a name.
Stem: Usually more than 1/2 above ground ovoid, obovoid, or cylindric with age to 9.5 x 7cm.
Tubercles: Grooved, stiff or ± flaccid 12-16 mm long; areolar glands absent.
Radial Spines: 20-30 per areole; white to cremy-white often with pinkish tips hardly distinguishable from centrals.
Central spines: 3-4 per areole, straight, spreading slightly longer than radials.
Flowers: Subapical, rose-pink to reddish pink, violet or magenta with darker midstripes.
Fruits: Green, exposed portions slowly turning dull brownish red, ovoid to obovoid, juicy; floral remnant persistent.
Seeds: Bright reddish brown.
Blooming season: Spring-late summer; fruiting 2-5 months after flowering.

Bibliography: Major references and further lectures
1) Edward Anderson “The Cactus family” Timber Press, Incorporated, 2001
2) Terry, M., Heil, K. & Corral-Díaz, R. 2013. Escobaria vivipara. The IUCN Red List of Threatened Species. Version 2015.1. <www.iucnredlist.org>. Downloaded on 13 June 2015.
3) 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
4) David R Hunt; Nigel P Taylor; Graham Charles; International Cactaceae Systematics Group. "The New Cactus Lexicon" dh books, 2006
5) Castetter, E.F., P. Pierce and K.H. Schwerin. “Reassessment of the genus Escobaria.” Cactus and Succulent Journal (US) 47(2):60-70.1975.
6) Leo J. Chance “Cacti and Succulents for Cold Climates: 274 Outstanding Species for Challenging Conditions” Timber Press, 19/giu/2012
7) N. L. Britton, J. N. Rose “The Cactaceae. Descriptions and Illustrations of Plants of the Cactus Family.” Volume 4, The Carnegie Institution of Washington, Washington 1923
8) Flora of North America Editorial Committee. “Flora of North America, volume 4.” Oxford University Press, New York.2003.