Body solitary or clustering, pale green. Ribs numerous often more than 100. Spines 6-18. Flowers less than 4 cm long.
NE Mexico
S. ochoterenaus Tiegel is similar but with fewer ribs, more spines and larger flowers with a distinct tube.
S. pentacanthus (Lem.) Britton & Rose from C Mexico has few areoles, each with 5 spines (uppermost one large and flattened) and relatively large whitish flowers with dark reddish stripe.
Source: (1997). Cactaceae. In: . Horticultural Flora of South-eastern Australia. Volume 2. Flowering plants. Dicotyledons. Part 1. The identification of garden and cultivated plants. University of New South Wales Press.
