Origin and Habitat: Southern Texas (Eagle Pass to Pecos River), south to Santa Rosa, Coahuila, Mexico, westward into Chihuahua.
Habitat and ecology: Apparently now extinct in Texas.

• Echinocereus dasyacanthus var. ctenoides (Engelm.) Backeb.
• Cereus ctenoides Engelm.
• Echinocereus ctenoides (Engelm.) Rümpler in C.F.Först.
• Echinocereus pectinatus subs. ctenoides (Engelm.) G.Frank
• Echinocereus pectinatus var. ctenoides (Engelm.) D.Weniger ex G.Frank
• Echinocereus spinosissimus var. ctenoides (Engelm.) Y.Itô

• Echinocereus dasyacanthus Engelm.
• Cereus dasyacanthus Engelm.
• Echinocereus pectinatus var. dasyacanthus (Engelm.) W.H.Earle ex N.P.Taylor
• Echinocereus dasyacanthus var. ctenoides (Engelm.) Backeb.
• Cereus ctenoides Engelm.
• Echinocereus ctenoides (Engelm.) Rümpler in C.F.Först.
• Echinocereus pectinatus subs. ctenoides (Engelm.) G.Frank
• Echinocereus pectinatus var. ctenoides (Engelm.) D.Weniger ex G.Frank
• Echinocereus spinosissimus var. ctenoides (Engelm.) Y.Itô
• Echinocereus dasyacanthus var. rectispinus Trocha & Fethke
• Echinocereus dasyacanthus subs. rectispinus (Trocha & Fethke) W.Blum, W.Rischer & Rutow
• Echinocereus deflexispinus (Monv. ex Labour.)
• Cereus deflexispinus Monv. ex Labour.
• Echinocereus hildmannii Arendt
• Echinocereus pectinatus var. neomexicanus (J.M.Coult.) L.D.Benson
• Cereus dasyacanthus var. neomexicanus J.M.Coult.
• Echinocereus roetteri var. neomexicanus (J.M.Coult.) A.D.Zimmerman
• Echinocereus rubescens Dams
• Echinocereus papillosus var. rubescens (Dams)
• Echinocereus steerae Clover
• Echinocereus spinosissimus var. steereae (Clover) Y.Itô

Description: Echinocereus dasyacanthusSN|8503]]SN|5533]] var. ctenoides is a cylindrical Echinocereus species very closely related to Echinocereus dasyacanthusSN|5533]]SN|5533]] and may not be specifically distinct. It differs somewhat in its spines and has a more southern range. The stems are banded with pink and grey as in the rainbow cactus (Echinocereus rigidissimusSN|8509]]SN|8509]]). The flowers are yellow, orange, or a blend of yellow and orange and very large for the size of the plant.
Stem: Simple or clustering to 6 stems, each heavily cylindric, elongated, 10-15(-40) cm long, to 8 (-10) cm in diameter.
Ribs: 15 to 17, low prominently interrupted by tubercles.
Areoles: Crowded together, short-elliptic.
Radial spines: 14-22, not spreading but standing out at an angle to the ribs.
Central spines: 2-4 (sometime as many as to 10), arranged in a single row or sometimes a little irregular, white with very light brown tips, never purplish or banded.
Flowers: Large, showy, mostly, orange-yellow, but also yellow or pink, up to 10 cm long, about as wide as long when fully expanded. Perianth segments linear to narrowly spatulate, ends erose, bright to reddish yellow upper part with bright orange midline, lower third green, center bright green. Filaments yellow. Style white to greenish-white. Stigma lobes 13 dark green. Ovary and fruit very spiny with some short white wool. Spines 14 -16 short, rigid, white with dark brown tips.
Fruits: 12-30 mm in diameter, spherical or egg-shaped, green then greenish-brown when ripe, covered with short wool, rigid spines, deciduous when fruit ripens.
Notes: Echinocereus dasyacanthusSN|5533]]SN|5533]] var. ctenoides is one of the least known of all Echinocerei, it was described by Engelmann over one hundred years ago. Engelmann had specimens from Bigelow, collected at Eagle Pass and near Santa Rosa, Coahuila, and those of Wright, collected by the lower Pecos River, which is not far front Eagle Pass. He stated that the plant "looked distinct enough from E. dasyacanthus"; and then he stated that "the flowerless plant so closely resemble E. pectinatus that it can hardly be distinguished from it except by the fewer ribs". In spite of its yellow flowers Backeberg finally call the cactus E. dasyacanthus var. ctenoides. In the 80th Del Weniger was unable to found any of these plants along the Rio Grande from below Eagle Pass to the Pecos, but in the mountains northwest of Santa Rosa in the adjacent part of Coahuila he found stands of small, few clustered Echinocerei almost exactly like E. pectinatus, except for their whiter spines, with 15 or 16 ribs, 2 to 4 centrals, and large, light-orange flowers. This plants were identified by Weniger as a form of E. pectinatus. Echinocereus pectinatusSN|5533]]SN|8503]]
var. wenigeri is considered by Frank (1997) to be a synonym of this species.

Bibliography: Major references and further lectures
1) Nathaniel Lord Britton, Joseph Nelson Rose “Cactaceae: Descriptions and Illustrations of Plants of the Cactus Family” Volume 3, 1922
2) Ellen Schulz Quillin, Robert Runyon “Texas Cacti: A Popular and Scientific Account of the Cacti Native of Texas” Texas Academy of Science, 1930
3) Del Weniger “Cacti of Texas and Neighboring States: A Field Guide” University of Texas Press, 1984
4) Lino Di Martino “Echinocereus” Cactus & Co. Special Issue Supplement to VOL. II N°3 July 1998