Origin and Habitat: Mexico (northern Sonora, north-western Chihuahua
Habitat: The reported habitat preference for limestone is erroneous; this species is a calcifuge, preferring soils poor in lime and usually acid.

• Echinocereus rigidissimus subs. rubispinus (G.Frank & A.B.Lau) N.P.Taylor
• Echinocereus pectinatus var. rubispinus G.Frank & A.B.Lau
• Echinocereus rigidissimus var. rubispinus (G.Frank & A.B.Lau) N.P.Taylor

• Echinocereus rigidissimus subs. rubispinus (G.Frank & A.B.Lau) N.P.Taylor
• Echinocereus pectinatus var. rubispinus G.Frank & A.B.Lau
• Echinocereus rigidissimus var. rubispinus (G.Frank & A.B.Lau) N.P.Taylor
• Echinocereus rigidissimus subs. rubispinus f. albiflorus hort.
• Echinocereus rigidissimus var. albiflorus hort.

• Echinocereus rigidissimus (Engelm.) Rose
• Cereus pectinatus var. rigidissimus Engelm.
• Echinocereus dasyacanthus var. rigidissimus (Engelm.) W.T.Marshall
• Echinocereus pectinatus var. rigidissimus (Engelm.) Rümpler in C.F.Först.
• Echinocereus pectinatus var. robustus
• Echinocereus rigidissimus f. cristata hort.

Description: Echinocereus rigidissimusSN|8509]]SN|8509]] subs. rubispinus is one of the local form of Echinocereus rigidissimusSN|8509]]SN|8509]]. It distinguishes for the very short dusty red-purple spines (not pink and white) and dull purple-red (not green) stigma lobes. It is also up to 50% smaller in all its parts. Its blossoms are bright magenta red and are large and showy in comparison with the small size of the stem. Its unique-looking spination makes it one the the best Echinocereus species.
Habit: It is a small columnar cactus that when mature will form a clump about to 60 cm wide by 25 cm tall.
Stems: Erect, short cylindrical, only get about 7cm thick.
Radial spines: 30-35 pectinate per areole and 6-10 mm in length in red and white bands, but more ruby/violet coluoured compared to the 'rigidissimus' subspecies, witch makes it a very attractive cactus. This is a Mexican form and does not turn grey like the Arizona form.
Flowers: Huge up to 10 cm wide. Beautiful bright pinkish-red or magenta or red with white throats. Blooms in ring on the crown of the stem in spring. The only downside is the flowers leave an unsightly scar when they drop off.
Fruits: Globose, greenish or dark purplish brownish very spiny, 3 cm in diameter, pulp white. Fruiting 3 months after flowering

Notes: Echinocereus rigidissimusSN|8509]]SN|8509]], lacking central spines, belongs to the E. reichenbachii group, unrelated to the superficially similar E. pectinatus group, which has at least microscopically visible stubs of central spines. It sometimes occurs with E. pseudopectinatus but without evidence of hybridization.

Bibliography: Major references and further lectures
1) 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
2) David Hunt, Nigel Taylor “The New Cactus Lexicon” DH Books, 2006
3) Edward F. Anderson “The Cactus Family” Timber Press, 2001
4) Nathaniel Lord Britton, Joseph Nelson Rose “Cactaceae: Descriptions and Illustrations of Plants of the Cactus Family” Volume 3, 1922
5) Paul S Martin, Davis Yetman, Mark Fishbein, Phil Jenkins, Thomas R. van Devender, & Rebecca K. Wilson "Gentry's Río Mayo Plants: The Tropical Deciduous Forest & Environs of Northwest Mexico" University of Arizona Press, 1998
6) Natt Noyes Dodge, Jeanne R. Janish "Flowers of the Southwest Deserts" Western National Parks Association, 01/gen/1985

Cultivation and Propagation: Echinocereus rigidissimusSN|8509]]SN|8509]] var. rubrispinus is not the easiest cactus to grow, but when grown well it is very attractive. Rot easily it is sensitive to overwatering (rot prone), so perfect soil drainage is a must.
Soil: It prefer a neutral to slightly acidic compost with plenty of extra grit.
Watering: Best if watered with rain water and given an occasional tonic of sequestrated iron.
Exposition: In the summer they need an airy location in bright sun; well watered when it's hot. To achieve the best spine colours give these plants lots of sun. In the winter light, cool, and absolutely dry conditions.
Hardiness: Very cold resistant above approx -12° C or less for short periods of time. In mild climate it may grow well when planted freely outside in well-drained soil.
Propagation: Seeds.