Name and species circumscription
Austrocactus philippii is the name accepted in Plants of the World Online, checked on 10 October 2026. Historical combinations include Cereus philippii, Echinocactus philippii and Erdisia philippii. The 2025 revision retains A. hibernus as a separate species, with which these plants were sometimes confused. [2-WWW] [Böhnert et al. 2025, taxonomic record and species description in the 2025 revision]
A solitary stem and spines
The stem usually grows upright and alone. It is cylindrical, green, around 20 cm long and 4 cm in diameter. Eight to ten ribs divide into small oval tubercles. Almost round areoles, around 4 × 4 mm, bear cream-coloured felt on young growth. [Böhnert et al. 2025, p. 401]
Three or four smooth central spines point outwards, roughly in a cross. They may be straight or hooked. Nine to ten translucent radial spines are needle-shaped and lie roughly in pairs. Features distinguishing the plant from A. diamantinus include its usually solitary stem and smaller number of stigma lobes. [Böhnert et al. 2025, p. 394, 397, 399, 401]
Flower and fruit
The funnel-shaped flower measures around 4 cm long and 3.5 cm in diameter. The tepals are spatulate, ending in a short point, and yellow with a reddish tint. The style is purplish red, and the stigma has 7–9 purple lobes. The dark green pericarpel bears white wool and fine bristles. [Böhnert et al. 2025, p. 401]
The shortly oval, green fruit measures around 1 cm. It is covered with bristles and white wool. On ripening, it dries and opens irregularly from the base. The greyish-brown seeds are curved, around 2 × 1.5 mm. Dry fruit structure and stigma colour help distinguish this species from A. hibernus, whose description includes pale stigmas and succulent fruits. [Böhnert et al. 2025, p. 401, 403, 406]
Andean valleys and branching after damage
The revision indicates sites in the Tunuyán, Tupungato and San Carlos departments of Mendoza Province, at elevations of 1900–2600 m. Plants occupy sandy soil between rocks, low shrubs and grassy vegetation. POWO also records central Chile. The detailed habitat description here corresponds to the revision's material, which focuses on Argentinian valleys. [Böhnert et al. 2025, p. 401] [2-WWW]
In the wild, plants are sometimes damaged by cattle, resulting in branching. Cultivated specimens usually remain solitary. A branched growth form therefore needs to be considered alongside damage marks and flower features. The authors retain the existing lectotype based on an illustration in the original description because they found no original specimen. [Böhnert et al. 2025, p. 401]
Related articles
Materials from the author's archive
The species also appears in Konrad Szychowski's private material archive. [Romulski b.d., file p. 4]
Synonyms and names in the literature
Cereus philippii · Echinocactus philippii · Erdisia philippii · Echinopsis philippii [2-WWW]