Origin and Habitat: Pediocactus simpsoniiSN|19699]]SN|19699]] var. minor is found at higher elevations (than var. simpsonii) mostly east of the Continental Divide in central Colorado, northern New Mexico, and southeastern Wyoming (and Utah?).
Altitude range: 2500-3300 metres above sea level.
Habitat and ecology: This species grows in dry to moist greasewood and grassland uplands.

• Pediocactus simpsonii var. minor (Engelm.) Cockerell
• Echinocactus simpsonii f. minor (Engelm.) Schelle
• Echinocactus simpsoni var. minor Engelm.
• Pediocactus simpsonii subs. bensonii (Engelm.) Hochstätter

• Pediocactus simpsonii (Engelm.) Britton & Rose
• Echinocactus simpsonii Engelm.
• Mammillaria simpsonii (Engelm.) M.E.Jones
• Pediocactus simpsonii f. acklinii Hochstätter
• Pediocactus simpsonii var. caespiticus Backeb.
• Pediocactus simpsonii f. campestris Hochstätter
• Pediocactus simpsonii f. dinosauriensis Hochstätter
• Pediocactus simpsonii f. flaminggorgensis Hochstätter
• Pediocactus simpsonii f. flinspachii Hochstätter
• Pediocactus simpsonii var. hermannii (W.T.Marshall) W.T.Marshall
• Pediocactus hermannii W.T.Marshall
• Pediocactus simpsonii subs. idahoensis Hochstätter
• Pediocactus simpsonii subs. indranus (Hochstätter) Hochstätter
• Pediocactus nigrispinus subs. indranus (Hochstätter) Hochstätter
• Pediocactus simpsonii var. indranus Hochstätter
• Pediocactus simpsonii f. kuenzleri Hochstätter
• Pediocactus simpsonii f. montanensis Hochstätter
• Pediocactus simpsonii f. muehlii Hochstätter
• Pediocactus simpsonii f. prairie Hochstätter
• Pediocactus simpsonii f. sandiamontanus Hochstätter

• Pediocactus simpsonii var. minor (Engelm.) Cockerell
• Echinocactus simpsonii f. minor (Engelm.) Schelle
• Echinocactus simpsoni var. minor Engelm.
• Pediocactus simpsonii subs. bensonii (Engelm.) Hochstätter

• Pediocactus simpsonii subs. robustior (J.M.Coult.) Hochstätter
• Echinocactus simpsonii var. robustior J.M.Coult.
• Echinocactus simpsonii var. robustior (J.M.Coult.) L.D.Benson
• Pediocactus robustior (J.M.Coult.) Arp

• Pediocactus simpsonii cv. Clumping Form

Description: Pediocactus simpsoniiSN|19699]]SN|19699]] var. minor is a controversial variety distinguished from stqandard Pediocactus simpsoniiSN|19699]]SN|19699]] by mostly solitary smaller stems and slender radial spines, but its stems tend to be much shorter (only 2-7 cm tall) and smaller in diameter than those of variety simpsonii. P. simpsonii is an exceedingly variable species. The segregation of the many forms, varieties, and subspecies on the basis of morphology, however, is difficult to support, given the continuous range of variation in stem size and flower colour over its geographic range. Some claim to be able to differentiate var. simpsonii from var. minor by size considerations, but the main way they have been distinguished is by geographical location, a poor way to tell them apart in cultivation. The var. minor is mostly restricted to far Northern New Mexico and Colorado. These populations do seem smaller and less robust overall (including in flower dimensions) than the simpsonii from Idaho, Nevada, Wyoming and Utah. But there are many doubt about that these differences are worthy of taxonomic rank.
Derivation of specific name: minor Latin, "smaller", "lesser". This specie as the name implies does not get as tall as some of the other Pediocactus simpsoniiSN|19699]]SN|19699]].
Stems: The var. minor is only 2-7 cm tall and 2-5 cm wide.
Central spines: 0.4 to 1.0 cm. long.
Lateral spines: Slender usually not interlocking.
Flowers: Flower colour is variable from white, pale pink, pink to magenta. It flowers pretty early in spring.
Note: The new combination Pediocactus simpsoniiSN|19699]]SN|19699]] subsp. bensonii ( Engelm. ) Hochstätter "Gen. Pediocactus, Navajoa, Toumeya" Revised 46. 1995 was based on (Basionym) Echinocactus simpsoniiSN|19701]]SN|19701]] var. minor. (Engelm.).

Bibliography: Major references and further lectures
1) Charles Hercules Boissevain, Carol Davidson “Colorado cacti: an illustrated guide describing all of the native Colorado cacti” Abbey garden press, 1940
2) Bethany Lynn Lewis “A Floristic Survey of the Arapaho National Wildlife Refuge Complex.” Traduci questa pagina 2008
3) Flora of North America Editorial Committee “Flora of North America: North of Mexico. Magnoliophyta: Caryophyllidae, part 1” Oxford University Press, 1993
4) Edward Anderson “The Cactus family” Timber Press, Incorporated, 2001
5) Urs Eggli, Leonard E. Newton “Etymological Dictionary of Succulent Plant Names” Springer Science & Business Media, 29 June 2013
6) Pediocactus simpsonii var minor forum in: CactiGuide.com On-line Guide to the positive identification of Members of the Cactus Family http://cactiguide.com/forum/viewtopic.php?t=15680

Cultivation and Propagation: Rot prone and not the easiest cactus to grow on it's own roots in cultivation it need a well drained, porous soil is preferred. Partial shading, especially during the hottest part of the summer, is helpful. Water should be provided in late winter, early spring (the main growing season), and also in Autumn, when flower buds are produced and it starts growing again. Do not l water during the winter seasons. Problems with this plants are most likely to result from improper watering. Too much water and the plant may rot; too little water may result in poor vigour or even death. They are good for outdoor cultivation in raised beds, rock gardens, balconies, window sills etc..
Frost Tolerance: Winter hardy from -10° to -25° C (depending on origin)
Propagation: Seeds. Temperature for optimum germination: night minimum approx 17 day maximum to near 40 C at any time of year with proper temperatures and daylength (ca.13-14 hours); it is possible to extend day-length with artificial lights. Anyway the seeds germinate slowly with difficulty and a low rate of success (But germiation is comparatively easy if compared with other Pediocactus and Sclerocactus species and often new seedling cluster spontaneously around the plant every year), scarification and stratification help, alternate freeze and thaw both wet and dry, but don’t keep wet, alternate wet and dry with changing temperature.
Germination can take several years so keep pot and try again next year. Seedlings do not do well either, and some die each year, for this reason plants are commonly grafted on hardy stocks like Opuntia humifusaSN|11629]]SN|11629]] in this case they are easy to grow and no special skill is required.