Acanthocalycium spiniflorum

Acanthocalycium spiniflorum is a species of flowering plant in the cactus family Cactaceae from Argentina.

Description
Acanthocalycium spiniflorum usually grows individually with spherical to slightly elongated shoots and reaches heights of growth of up to 60 cm with diameters of 10 to 15 cm. There are 16 to 20, up to 1 cm high ribs, which are somewhat divided into humps. The 10 to 20 straight, needle-like spines are flexible, yellowish to brown and have a darker tip. They turn gray with age. It produces many flowers in summer, that are funnel-shaped to bell-shaped flowers which may be purple, pink or white., have a length of up to 4 cm and have the same diameter.

Under its synonym Echinopsis spiniflora this plant has won the Royal Horticultural Society's Award of Garden Merit.

Distribution
Acanthocalycium spiniflorum is widespread in the Argentine provinces of Córdoba and San Luis at altitudes of 1000 to 1500 meters.

Taxonomy
The first description as Echinocactus spiniflorus by Karl Moritz Schumann was published in 1903. The specific epithet spiniflorus is derived from the Latin words spina for 'sting' or 'thorn' and florus for '-flowered' and refers to the scales on the flower tube of the species. Curt Backeberg placed the species in the genus Acanthocalycium in 1936. Further nomenclature synonyms are Echinopsis spiniflora (K. Schum.) A. Berger (1929), Spinicalycium spiniflorum (K. Schum.) Frič (1935, nom. inval. ICBN article 43.1) and Lobivia spiniflora (K.Schum.) Rausch (1987).