Stem structure
The classical account reports stems reaching about 3 m long and 2–5 cm in diameter. They are initially upright, later creeping or hanging according to available support. They have 10–13 low rounded ribs. Closely spaced areoles produce slender spines ranging from white to brownish, often with darker tips. Stem slenderness and changing orientation give the plant its characteristic three-dimensional habit. [Britton and Rose 1920]
Flowers and fruits
Flowers arise from upper areoles, sometimes at the stem tip. In the monographic account they are 15–19 cm long and about 8 cm wide when open. The white inner tepals contrast with the elongated tube bearing areoles and bristles. Ripe fruits are red, about 4 cm long, with deciduous spines. The black seeds are relatively large, reaching about 5 mm in that account. [Britton and Rose 1920]
Distribution and conservation
The native range is Mexico, primarily in seasonally dry tropical environments. Plants outside the native range have also been recorded in South Africa and Australia. POWO displays an IUCN assessment of LC, Least Concern, published under the synonym Peniocereus serpentinus. [2-WWW]
Propagation through areole activation
A tissue-culture study used stem pieces from juvenile greenhouse plants aged 2–3 years. Buds present in the areoles were stimulated on Murashige and Skoog medium. Among the tested treatments, most new shoots were obtained with benzyladenine at 2 mg/l. New shoots developed from existing buds, a process described as axillary proliferation. [Pérez Molphe Balch et al. 1998]
In the next stage, the best rooting among the tested media was obtained with indole-3-acetic acid at 0.5 mg/l. Roots formed on 85% of shoots. Four weeks after transfer to potting substrate, 70% of plants previously rooted in culture had survived. These percentages concern successive stages of the particular laboratory experiment. [Pérez Molphe Balch et al. 1998]
Materials from the author's archive
The species also appears in Konrad Szychowski's private material archive. [Kreuzinger 1935]
Synonyms and names in the literature
Cactus ambiguus · Cactus serpentinus · Cereaster serpentinus · Cereus ambiguus · Cereus ambiguus var. strictior · Cereus kalbreyerianus · Cereus serpentinus · Cereus serpentinus var. splendens · Cereus splendens · Echinocereus serpentinus · Echinocereus splendens · Nyctocereus castellanosii · Nyctocereus kalbreyerianus · Nyctocereus serpentinus subsp. splendens · Nyctocereus serpentinus var. ambiguus · Nyctocereus serpentinus var. pietatis · Nyctocereus serpentinus var. splendens · Nyctocereus serpentinus var. strictior · Peniocereus castellanosii · Peniocereus serpentinus · Peniocereus serpentinus subsp. pietatis [2-WWW]