From Cacti by Borg, 419. 1970
treated as a synonym of S. truncata by B&T 1995
Zygocactus truncatus var. Altensteinii (Pfeiff) = Epiphyllum Altensteinii Pfeiff.
From the same district in Brazil; differs from the typical form by the teeth on each side of the joint being more pronounced and acute. The flowers are of the same shape and size, or slightly larger, and the colour is carmine scarlet to scarlet, or brick red, or crimson. The habit of growth as a hanging plant is the same, but is distinctly more vigorous.