Name and straight spines
The accepted name is Cochemiea halei (Brandegee) Walton. The basionym Mammillaria halei Brandegee was published in 1889, and the combination in Cochemiea in 1899. The epithet's authorship refers to T. S. Brandegee. [2-WWW]
The plant forms clusters of stems lying along the ground. Comparison with C. thomasii in the 2020 protologue gave C. halei 6–9 straight central spines 20–25 mm long and 15–22 radial spines. Flowers measured 35–50 mm long, and red club-shaped fruits about 12 mm. In the 2021 plastid analysis, C. halei material grouped with C. poselgeri, some of whose spines are hooked. [García Morales et al. 2020, García Morales et al., p. 5, table 1. Breslin et al., p. 313, fig. 2] [Breslin et al. 2021, García Morales et al., p. 5, table 1. Breslin et al., p. 313, fig. 2]
Islands and a substrate mosaic
The distribution study primarily covered the Magdalena archipelago, including Magdalena and Santa Margarita islands and the Cabo San Lázaro area. It also included a report of a very small population on the adjacent mainland. Eight field visits over four years provided 1227 georeferenced occurrence records, reduced to 44 presence points after spatial filtering. [Breslin et al. 2020, p. 13212–13215, 13218]
About 60% of observations came from soils formed on ultramafic rocks. This association is facultative, since plants also occurred on other substrates. Two soil categories were included in the model, based on field observations and a geological map. [Breslin et al. 2020, pp. 13213–13215, 13218–13220]
Prognozowana powierzchnia siedlisk
The regression-tree model that transferred best between datasets combined four climatic variables with soil category. Annual temperature range and mean temperature of the warmest quarter had the largest combined contribution to the model. A resolution of about 1 km limited recognition of fine differences between rocks, slopes and crevices. [Breslin et al. 2020, p. 13214–13218; ryc. 3–5]
For the 2050 and 2070 time horizons and four RCP scenarios, a loss of 46–55% of habitat area currently considered suitable was projected. The model also indicated some new suitable areas, making the net loss 21–53%. These are changes in modelled area at a specified suitability threshold, without conversion to numbers of living plants. Potential area on the higher ridges of Santa Margarita would also require successful dispersal and population establishment. [Breslin et al. 2020, p. 13216–13220; tabela 1, ryc. 6–8]
Related articles
Materials from the author's archive
The species also appears in Konrad Szychowski's private material archive. [Anonim b.d.y, file p. 1] [Lindsay 1959, file p. 5, 6] [Gorelick 2007, file p. 1, 2]
Synonyms and names in the literature
Cactus halei · Mammillaria halei [2-WWW]