Aporocactus martianus

Aporocactus martianus (syn. "Disocactus martianus") is a species of cactus found in Oaxaca, Mexico. 
Description.
"Disocactus martianus" grows creeping, occasionally forming lithophytic with aerial roots. It is a species of fleshy, cylindrical suspended or creeping cactus with stems up to 1.5 meters long and up to 2.5 centimeters thick, sometimes with aerial roots, with 8 to 10 slightly wart-shaped ribs; 3 or 4 central pale brown spines up to 12 mm long and 6 to 20 radial spines are light yellowish and only 5 to 7 millimeters long. The bright red flowers are diurnal and produced in summer, 10 to 12 centimeters in diameter and a length of 5 to 7 centimeters. The flowers stay open for a couple of days. They are followed by globose fruits of green color and 2 cm in diameter. It is viviparous.
Taxonomy & Systematics.
It was first described as "Cereus martianus" in 1837 by Ludwig Georg Karl Pfeiffer. Wilhelm Barthlott moved the species to Disocactus in 1991
The following species and varieties are synonyms: 
In their synopsis of the tribe "Hylocereeae" from 2017, Nadja Korotkova, Thomas Borsch and Salvador Arias interpret the species as a synonym of "Aporocactus martianus".