One species and different classifications
POWO accepts the genus Ortegocactus, published by Alexander in 1961, with one species, O. macdougallii. In the 2021 analysis by Breslin and colleagues, the species was transferred to broadly circumscribed Cochemiea. In the current POWO record, Cochemiea macdougallii remains a synonym of Ortegocactus macdougallii. Both names refer to the same taxon. [2-WWW] [2-WWW] [Breslin et al. 2021, POWO, as of 11 October 2026. Breslin et al., p. 319]
In 2023, Chincoya and colleagues combined an analysis of 52 plastid loci with a biogeographic reconstruction. They recognised an Ortegocactus lineage alongside the Neolloydia lineage and various groups of traditional Mammillaria. They argued for retaining separate genera, citing morphological, habitat and historical differences. Shared ancestry of a group in the DNA tree and the decision to name it as one genus are two stages of data interpretation. [Chincoya et al. 2023, pp. 13–15]
Globose stem and yellow flowers
The stem of O. macdougallii is globose, covered with flat, rhomboid tubercles. The areoles are dimorphic. Hairs and spines occur in the upper part, while flowers develop in the tubercle axils. A groove is sometimes visible. There is one straight central spine. The yellow flowers have radial symmetry, and the fruits are globose and dull red. [Vázquez-Sánchez 2012, Vázquez-Sánchez, doctoral thesis, January 2012, printed p. 89, description of the genus Ortegocactus]
A small tubercle as regeneration material
Arellano-Perusquía and colleagues studied stem fragments and tubercles of O. macdougallii. The explants, fragments used to initiate a culture, included one to three areoles. Under controlled medium conditions, pre-existing areole meristems were activated, and additional buds formed at the edges and bases of fragments, outside the areoles. Propagation thus involved both growth of existing primordia and adventitious organogenesis. [Arellano-Perusquía et al. 2013, pp. 161–165]
The response depended on the proportions of the auxin NAA and cytokinin BA. During multiplication, an average of about five or six shoots formed per explant. At the higher BA concentrations tested, shoots with altered shapes also appeared, described by the authors as fasciated. The regenerants could then form adventitious roots. Full conditions and data for this experiment are presented in the species account and the article on organogenesis. [Arellano-Perusquía et al. 2013, p. 163–165, tabele 2–4]
A small range in Oaxaca
The current POWO range of O. macdougallii includes Oaxaca. The 2013 paper places its natural sites in a small area of the municipality of San José Lachiguiri. The authors discuss substrate degradation and plant collecting as threats to local populations. They conducted the propagation study using nursery material, without taking tubercles from plants at natural sites. [2-WWW] [Arellano-Perusquía et al. 2013, Arellano-Perusquía et al., pp. 160–161]