Stems and spines
In the original description, plants were usually seven to ten metres tall, exceptionally reaching twelve. Sterile stem portions bear four, occasionally five central spines. One projects perpendicularly and has a polyhedral cross section. Areoles in the flowering zone carry numerous slender bristle-like spines. The longest may twist spirally. This variation along a branch is important when comparing plants. [Gama-López and Arias 1998]
Flowers, fruits and seeds
Funnel-shaped flowers develop near stem tips and open at night. The description gives a length of six to eight centimetres. The fleshy floral tube has fleshy bracts and usually bare axillary areoles, whereas wool covers the pericarpel. The fleshy red-purple fruit opens at maturity. These traits help distinguish P. tepamo from the species with which it was formerly compared. [Gama-López and Arias 1998]
Seasonally dry forest of the Balsas basin
The original localities were in Michoacán near the Infiernillo reservoir in the lower Balsas basin. The authors reported elevations of 150 to 1100 m and tropical deciduous forest. Flowering was observed in July and August. The current POWO record includes Michoacán and Guerrero. Distinguishing the originally documented sites from the present database range preserves the history of knowledge about the species. [Gama-López and Arias 1998] [2-WWW]
Materials from the author's archive
The species also appears in Konrad Szychowski's private material archive. [Kaktusy itd. 2008]