Origin and Habitat: Hidalgo, Queretaro, Veracruzm, Mexico, Oaxaca and puebla, north and central Mexico.
Altitude: 1500-2600 metres above sea level.
Habitat: Mattoral xerophilo, pastizal and open juniper-pinion forests.

• Stenocactus arrigens (Link ex A.Dietr.) A.Berger
• Brittonrosea arrigens Speg.
• Echinocactus arrigens Link ex A.Dietr.
• Echinofossulocactus arrigens (Link ex A.Dietr.) Britton & Rose
• Echinofossulocactus crispatus f. arrigens (Link ex A.Dietr.) P.V.Heath
• Echinofossulocactus obvallatus var. arrigens (Link ex A.Dietr.) J.Meyran
• Efossus arrigens (Link ex A.Dietr.) Orcutt

• Stenocactus crispatus (DC.) A.Berger
• Brittonia crispata (DC.) Speg.
• Brittonrosea crispata (DC.) Speg.
• Echinocactus crispatus DC.
• Echinocactus undulatus A.Dietr.
• Echinofossulocactus crispatus (DC.) Lawr. in Loudon
• Efossus crispatus (DC.) Orcutt
• Ferocactus crispatus (DC.) N.P.Taylor
• Stenocactus acroacanthus (D.C.Stieber) W.T.Marshall & T.M.Bock
• Echinocactus acroacanthus D.C.Stieber
• Echinofossulocactus acroacanthus (D.C.Stieber) G.D.Rowley
• Echinofossulocactus crispatus f. acroacanthus (D.C.Stieber) P.V.Heath
• Stenocactus anfractuosus (Mart. ex Pfeiff.) A.Berger
• Brittonrosea anfractuosa Speg.
• Echinocactus anfractuosus Mart. ex Pfeiff.
• Echinofossulocactus anfractuosus (Mart. ex Pfeiff.) Lawr. in Loudon
• Echinofossulocactus crispatus f. anfractuosus (Pfeiff.) P.V.Heath
• Efossus anfractuosus Orcutt
• Stenocactus arrigens (Link ex A.Dietr.) A.Berger
• Brittonrosea arrigens Speg.
• Echinocactus arrigens Link ex A.Dietr.
• Echinofossulocactus arrigens (Link ex A.Dietr.) Britton & Rose
• Echinofossulocactus crispatus f. arrigens (Link ex A.Dietr.) P.V.Heath
• Echinofossulocactus obvallatus var. arrigens (Link ex A.Dietr.) J.Meyran
• Efossus arrigens (Link ex A.Dietr.) Orcutt
• Stenocactus arrigens f. cristatus hort.
• Echinofossulocactus arrigens f. cristatus hort.
• Stenocactus confusus (Britton & Rose) F.M.Knuth in Backeb. & F.M.Knuth
• Brittonrosea confusa Speg.
• Echinofossulocactus confusus Britton & Rose
• Echinofossulocactus crispatus f. confusus (Britton & Rose) P.V.Heath
• Efossus confusus (Britton & Rose) Orcutt
• Stenocactus crispatus f. cristatus hort.
• Echinofossulocactus crispatus f. cristatus hort.
• Stenocactus crispatus f. ensiferus (Lem.)
• Echinocactus anfractuosus var. ensiferus (Lem.) Salm-Dyck
• Echinocactus ensiferus Lem.
• Echinofossulocactus crispatus f. ensiferus (Lem.) P.V.Heath
• Stenocactus crispatus f. undulatus (A.Dietr.)
• Echinofossulocactus crispatus f. undulatus (A.Dietr.) P.V.Heath
• Stenocactus dichroacanthus (Mart. ex Pfeiff.) A.Berger ex Backeb. & F.M.Knuth
• Brittonrosea dichroacantha (Mart. ex Pfeiff.) Speg.
• Echinocactus dichroacanthus Mart. ex Pfeiff.
• Echinocactus dichroacanthus spinosior Monv. in Labour.
• Echinofossulocactus crispatus f. dichroacanthus (Mart.) P.V.Heath
• Echinofossulocactus dichroacanthus (Mart. ex Pfeiff.) Britton & Rose
• Efossus dichroacanthus (Mart. ex Pfeiff.) Orcutt
• Stenocactus fasciculatus hort.
• Echinofossulocactus fasciculatus
• Stenocactus flexispinus hort.
• Echinocactus flexispinus Salm-Dyck non Engelm.
• Echinofossulocactus crispatus f. flexispinus (Salm-Dyck) P.V.Heath
• Echinofossulocactus flexispinus (Salm-Dyck) Bravo
• Stenocactus gladiatus (Link & Otto) A.Berger ex Backeb. & F.M.Knuth
• Brittonrosea gladiata (Link & Otto) Speg.
• Echinocactus gladiatus Link & Otto
• Echinocactus gladiatus intermedius Lem. in Labour.
• Echinocactus gladiatus ruficeps Lem. in Labour.
• Echinofossulocactus gladiatus (Link & Otto) Lawr. in Loudon
• Efossus gladiatus (Link & Otto) Orcutt
• Melocactus gladiatus Link & Otto
• Stenocactus grandicornis (Lem.) A.Berger ex Backeb. & F.M.Knuth
• Brittonrosea grandicornis (Lem.) Speg.
• Echinocactus grandicornis Lem.
• Echinocactus grandicornis var. fulvispinus Salm-Dyck
• Echinofossulocactus crispatus f. grandicornis (Lem.) P.V.Heath
• Echinofossulocactus grandicornis (Lem.) Britton & Rose
• Efossus grandicornis (Lem.) Orcutt
• Stenocactus phyllacanthus f. grandicornus hort.
• Stenocactus guerraianus f. cristatus
• Echinofossulocactus guerraianus f. cristatus
• Stenocactus hastatus (Hopffer ex K.Schum.) A.Berger
• Brittonrosea hastata (Hopffer ex K.Schum.) Speg.
• Echinofossulocactus hastatus (Hopffer ex K.Schum.) Britton & Rose
• Echinofossulocactus sulphureus f. hastatus (Hopffer ex K.Schum.) P.V.Heath
• Efossus hastatus (Hopffer ex K.Schum.) Orcutt
• Stenocactus lamellosus hastatus hort.
• Stenocactus kellerianus hort.
• Echinofossulocactus crispatus f. kellerianus (Krainz) P.V.Heath
• Echinofossulocactus kellerianus Krainz
• Stenocactus lamellosus (A.Dietr.) A.Berger
• Brittonrosea lamellosa (A.Dietr.) Speg.
• Echinocactus lamellosus A.Dietr.
• Echinocactus lamellosus var. fulvescens Salm-Dyck
• Echinofossulocactus crispatus f. lamellosus (A.Dietr.) P.V.Heath
• Echinofossulocactus lamellosus (A.Dietr.) Britton & Rose
• Efossus lamellosus (A.Dietr.) Orcutt
• Stenocactus lancifer (A.Dietr.) A.Berger ex Backeb. & F.M.Knuth
• Brittonrosea lancifera (A.Dietr.) Speg.
• Echinocactus lancifer A.Dietr.
• Echinofossulocactus crispatus f. lancifer (A.Dietr.) P.V.Heath
• Echinofossulocactus lancifer (A.Dietr.) Britton & Rose
• Efossus lancifer (A.Dietr.) Orcutt
• Stenocactus longispinus hort.
• Echinofossulocactus arrigens var. longispinus (Pechanek) hort.
• Echinofossulocactus dichroacanthus var. longispinus (Pechanek) hort.
• Echinofossulocactus longispinus Pechanek
• Stenocactus crispatus f. longispinus hort.
• Stenocactus multiareolatus Bravo
• Echinofossulocactus multiareolatus Bravo
• Stenocactus violaciflorus (Quehl) A.Berger
• Brittonrosea violaciflora (Quehl) Speg.
• Echinocactus violaciflorus Quehl
• Echinofossulocactus crispatus f. violaciflorus (Quehl) P.V.Heath
• Echinofossulocactus violaciflorus (Quehl) Britton & Rose
• Efossus violaciflorus (Quehl) Orcutt
• Stenocactus dichroacanthus subs. violaciflorus (Quehl) U.Guzmán & Vázq.-Ben.
• Stenocactus dichroacanthus var. violaciflorus (Quehl) Bravo
• Stenocactus xiphacanthus (Miq.) hort., nov. comb. ined.
• Echinocactus xiphacanthus Miq.
• Echinofossulocactus xiphacanthus (Miq.) Backeb.

Description: Stenocactus arrigensSN|6244]]SN|6244]]is (Formerly known as Echinofossulocactus arrigensis) is one of the species with the prettiest spination, spine are flattened, ferocious-looking with one very long central spine (up to 7-9 cm long) directed upwards. The ribs are thin with very undulated or curled ridges. Stenocactus arrigensSN|3443]]SN|6244]]is is to all intents and purposes a synonym of Stenocactus crispatusSN|6244]]SN|3443]]. The plant still found in cultivation under the name of Stenocactus arrigensSN|6244]]SN|6244]]is are quite variable and the dissimilarity among seedlings spination may be considerable.
Habit: It is a perennial stem succulent growing solitary (or rarely branching from the base).
Stem: Up to 20 cm tall, 10 cm wide, globose, obovoid or short-cylindric, somewhat depressed at apex, bluish-green, dark matt green or dark olive-green.
Ribs: (25-)30-60(-80) thin, more or less folded, with very regularly and attractively waived, depressed in the region of areoles. The flattened, wavy or curled ridges of this species are characteristic of other kinds of Echinofossulocactus.
Areoles: 1 to 3 in each ribs, woolly in youth, later naked.
Radial spines: Usually 4 to 6 flattened, whitish to brownish, 0,5 to 1 cm long and about 0,6-1 mm wide at the base.
Central spine: 3-4 very flattened, whitish, yellowish, brownish to almost black, often darker at the tip, directed upwards ± rigid, ferocious-looking, straight or curved, unequal with one very long (from 1 to 10 cm long) and 1-5 mm wide at the base
Flowers: Central, rather small, up to 4 cm long, funnel-shaped. Perianth segments in two series, pale pink with a purplish midrib, oblong-linear, acute. Flower tube well developed, covered with imbricating scales.
Blooming season: Late spring to summer.
Fruits: 8-12 mm long, 4-6 mm wide, obovoid reddish to greysh, dry at maturity.
Seeds: 1 mm long x 0,9 mm wide, pyriform to reniform, black. Head with celled and wavy wall.
Remarks: Identifying the species of an Echinofossulocactus is as difficult as identifying the genus is easy. For the most part, they tend to look alike, and there are far more names than there are species.

Notes: Stenocacti are commonly called wave or brain cacti because of their crinkly appearance. Because the undulating ribs on this small, spherical cactus are so numerous and so closely spaced that most of what you see is the wavy brain-like surface of the plant.

Bibliography: Major references and further lectures
1) Friedrich Ritter “Kakteen in Südamerika Ergebnisse meiner 20jährigen Feldforschungen: Volume 4: Peru” 1981
2) Edward Anderson “The Cactus family” Timber Press, Incorporated, 2001
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) Hans Hecht “Cacti & succulents” Sterling Pub. Co., 1997
6) Walther Haage "Kakteen von A bis Z" , Quelle & Meyer Verlag: Heidelberg, 1986
7) Urs Eggli "Das große Kakteen-Lexikon" Ulmer, Stuttgart 2005
8) David Hunt "CITES Cactaceae Checklist" Second Edition. 1999
9) Nigel Paul Taylor "A commentary on the genus Echinofossulocactus Lawr." In: Cactus and Succulent Journal of Great Britain. Volume 41, page 35–42 1979

Cultivation and Propagation: Stenocactus arrigensSN|6244]]SN|6244]] is easy to to care cactus, recommended for any collection that needs lots of light with ample airflow.
Growth rate: It is a small growing, but easily flowering species.
Soils: It needs regular cacti soil with little organic matter (peat, humus).
Repotting: Repotting every other year. As it is especially prone to rot under-pot in a smaller container filled with very porous compost. Use pot with good drainage.
Watering: Water regularly in summer, but do not overwater (very wet-sensitively, especially in light of its succulent root system), allow to dry between watering. Its roots are easily lost in pots that stay damp for any length of time. It should not be watered at all in winter. In the rest period no high atmospheric humidity!! Care must be taken with watering as they tends to become swollen and untidy in growth habit if given too much water and shade.
Fertilization: During the growing season enrich the soil using a fertilizer rich in potassium and phosphorous, but poor in nitrogen, because this chemical element doesn’t help the development of succulent plants, making them too soft and full of water.
Hardiness: Reputedly sensitive to frost , but less so if kept on the dry side prior to, and during, cold weather (hardy to -5° C for short periods). However some warmth throughout the year will increase the grower's success (minimum 5° to 8°C during rest season).
Exposition: Outside bright sun it likes strong sunshine, but is tolerant and do well with light shade during the hot Summer months, inside it needs bright light, and some direct sun. Subject to sunburn if exposed to direct sun for too long. Tends to bronze in strong light, which encourages flowering and heavy wool and spine production.
Uses: It is an excellent plant for container growing. It always looks good and stays small. It look fine in a cold greenhouse and frame.
Pests & diseases: It may be attractive to a variety of insects, but plants in good condition should be nearly pest-free, particularly if they are grown in a mineral potting-mix, with good exposure and ventilation. Nonetheless, there are several pests to watch for:
- Red spiders: Sensitive to red spider mite. Overhead watering is helpful in controlling mites.
- Mealy bugs: Occasionally mealy bugs they develop aerial into the new growth among the wool with disfiguring results, but the worst types develop underground on the roots and are invisible except by their effects.
- Scales: Scales are rarely a problem.
- Rot: Rot it is only a minor problem with cacti if the plants are watered and “aired” correctly. If they are not, fungicides won't help all that much.
Propagation: Seeds (usually). Seeds germinate in 7-14 days at 21-27° C in spring, remove the glass cover gradually as the plants develops and keep ventilated, no full sun for young plants! The seedlings should not be disturbed until they are well rooted, after which they can be planted separately in small pots.