Origin and Habitat: USA, South Utah, Nevada, California (Dead Valley area) Arizona.
Altitude: 500-1400 metres above sea level.
Habitat: It grows in a very arid and dry environment, in the Mojave desert scrub and upper edge of Sonoran desert scrub on rocky hillside on gravelly hills in lime-stone impregnated soil.

• Echinomastus johnsonii (Parry ex Engelm.) E.M.Baxter in E.M.Baxter
• Echinocactus johnsonii Parry ex Engelm.
• Ferocactus johnsonii (Parry ex Engelm.) Britton & Rose
• Neolloydia johnsonii (Parry ex Engelm.) L.D.Benson
• Pediocactus johnsonii (Engelm.) Halda
• Sclerocactus johnsonii (Parry ex Engelm.) N.P.Taylor
• Thelocactus johnsonii (Parry ex Engelm.) W.T.Marshall

• Echinomastus johnsonii (Parry ex Engelm.) E.M.Baxter in E.M.Baxter
• Echinocactus johnsonii Parry ex Engelm.
• Ferocactus johnsonii (Parry ex Engelm.) Britton & Rose
• Neolloydia johnsonii (Parry ex Engelm.) L.D.Benson
• Pediocactus johnsonii (Engelm.) Halda
• Sclerocactus johnsonii (Parry ex Engelm.) N.P.Taylor
• Thelocactus johnsonii (Parry ex Engelm.) W.T.Marshall
• Echinomastus johnsonii var. lutescens (Parish) Wiggins in Shreve & Wiggins
• Echinocactus johnsonii subs. lutescens (Parish) A.E.Murray
• Echinocactus johnsonii var. lutescens Parish
• Neolloydia johnsonii var. lutescens (Parish) W.T.Marshall ex R.G. Engard
• Echinomastus johnsonii var. octocentrus J.M.Coult.

Description: Echinomastus johnsoniiSN|14880]]SN|14880]] is a small “barrel cacti” almost completely hidden by the interlocking spines. Usually solitary (or occasionally branching after injury to the apical bud). This plant varies geographically in both flower and spine colour.
Stems: Ovoid to ellipsoid-cylindroid, 10-25 cm long, 7-15 cm in diameter. Apex more or less devoid of spines, but with a heavily felted-over circular patch 1-1,5 cm in diameter at the apex.
Ribs: (13-)18-21, narrow, undulate, strongly indented just above each tubercle and rising gradually to the next. Tubercles protruding approx 5-8 mm.
Areoles: (14-)21-26 mm apart along ribs with a short, narrow woolly groove running from the upper margin of the areole to the axil of the tubercle, areolar glands present at least seasonally. Spines 13-24 per areole, spreading, often intricately intertangled, acicular, greysh to pale yellow, tinged in pink-reddish, lavender to maroon and often blackening in age.
Radial spines: 9-16 per areole, stouter, more or less bulbous at the base, divaricately spreading; abaxial (shortest) radial spine 6-19 mm; adaxial and lateral (longest) radial spines ca. 27-40 mm (often lighter in colour)
Central spines: 4-9 per areole, present at all ages, spreading straight or slightly curving, never hooked, 27-41 long.
Flowers: Funnel form 4-6 cm long, 4-7,5 cm in diameter; inner tepals yellow or pink to magenta with a silvery sheen, basal portions blotched with maroon . Scale of the ovary obtuse, membranous on margins.Stigma lobes yellowish white to green.
Blooming season: Flowering (Feb-)Mar-May; fruiting Apr-Jun.
Fruits: Green drying to tan, nearly naked, dehiscent only along single, longitudinal split, spheric to oblong, 10-18 mm.
Seeds: Papillate, finely reticulate-pitted, broader then long.
Note: The yellow-flowered plants have been named E. johnsonii var. lutescens. The pink-flowered plants occur in separate populations, as far as is known, to the north of the yellow-flowered plants.

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) Brian Loflin, Shirley Loflin “Texas Cacti: A Field Guide” Texas A&M University Press, 26/ott/2009
5) Albert Michael Powell, James F. Weedin “Cacti of the Trans-Pecos and Adjacent Areas” Texas Tech University Press, 2004
6) Del Weniger “Cacti of the Southwest: Texas, New Mexico, Oklahoma, Arkansas, and Louisiana” University of Texas Press, 1969
7) “Rare Plants of Texas: A Field Guide” Texas A&M University Press, 2007
8) Roland H. Wauer, Carl M. Fleming “Naturalist's Big Bend: An Introduction to the Trees and Shrubs, Wildflowers, Cacti, Mammals, Birds, Reptiles and Amphibians, Fish, and Insects“ Texas A&M University Press, 2002
9) Butterworth, C., Baker, M. & Porter, J.M. 2013. Sclerocactus johnsonii. In: IUCN 2013. "IUCN Red List of Threatened Species." Version 2013.2. <www.iucnredlist.org>. Downloaded on 06 April 2014.

Cultivation and Propagation: This is one of the most beautiful cacti but rarely seen in cultivation, it needs perfect drainage to flourish. It is quite difficult to grow on its own roots. Very easily rot! It’s thought that’s better to watch this species in photo or in the natural habitat rather than to try to cultivate it. For this reasons the plant is often grafted on a frost hardy stock.
This plant need full sun and above all a very good ventilation, especially in winter. Keep totally dry during winter. It can tolerate temperature below zero (-15° C or less). Mature individuals - if the growing conditions are not optimal, easily rot and die.
Propagation: Seeds are relatively difficult to germinate (only a limited percentage of seeds germinate). Grafting is often used to speed growth rate and to create a back-up for plants in collection.