Mammillaria elongata D C.

Clustering, body elongate, 1-3 cm wide. Tubercles prominent. Axils bare. Central spines 0(-1). Radial spines 15-20, whitish to yellow or brown, radiating evenly or erect. Flowers pale to deep yellow, 1 cm long and wide. Fruit red. [M. echinaria DC.]

C Mexico

Source: Thompson, A, ; Forbes, S.; Spencer, R. (1997). Cactaceae. In: Spencer, R.. 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.

kingdom Plantae
phylum   Tracheophyta
class    Magnoliopsida
superorder     Caryophyllanae
order      Caryophyllales
family       Cactaceae
genus        Mammillaria Haw.