Pelecyphora strobiliformis

Name and origin

POWO accepts Pelecyphora strobiliformis (Werderm.) Frič & Schelle ex Kreuz. as a species of northeastern Mexico. The basionym, the earlier name on which the combination is based, was published in 1927 as Ariocarpus strobiliformis. The name Encephalocarpus strobiliformis from 1929 refers to the same species and still appears in older literature and collection descriptions. [2-WWW] [Sánchez et al. 2022, POWO, as of 11 October 2026. Sánchez et al., p. 141]

The 2002 experiment lists sites in San Luis Potosí, Tamaulipas and Nuevo León. The 2022 taxonomic paper identifies a neotype from near Miquihuana in Tamaulipas, collected in January 1961. A neotype is a specimen chosen to define the application of a name when the original material is unavailable. This document links the name to specific historical material. [Pérez-Molphe-Balch and Dávila-Figueroa 2002, Pérez-Molphe-Balch and Dávila-Figueroa, p. 73. Sánchez et al., p. 141] [Sánchez et al. 2022, Pérez-Molphe-Balch and Dávila-Figueroa, p. 73. Sánchez et al., p. 141]

A body of triangular tubercles

The stems are usually solitary, sometimes forming clumps. The 2002 characterisation gives a body up to about 3.5 cm high and 8 cm in diameter. Kew's botanical account describes triangular tubercles that give the stem a cone-like appearance. In its habitat, the flattened above-ground part barely projects above the ground. This structure distinguishes the species from P. aselliformis, with elongated spiny areoles resembling woodlice. [Pérez-Molphe-Balch and Dávila-Figueroa 2002, Pérez-Molphe-Balch and Dávila-Figueroa, p. 73. Kew, p. 27] [Sajeva et al. 2012, Pérez-Molphe-Balch and Dávila-Figueroa, p. 73. Kew, p. 27]

The tubercles have a vestigial groove homologous to the grooves of species from the former Escobaria. The short form of this structure and the highly modified tubercle shape are developmental characters of classical Pelecyphora. In the 2022 study, both species were found to be closely related to P. chihuahuensis and P. tuberculosa, which differ in the appearance of the stem surface. [Sánchez et al. 2022, p. 119, 124, ryc. 1–2]

Flower, seed coat and a similar epithet

The outer tepals have finely fringed, ciliate margins. In the taxonomic discussion, this character was described as consistent in P. strobiliformis and variable in P. aselliformis. The seed coat of classical Pelecyphora is pitted because the thin outer cell wall collapses across its entire surface. These characters connect the flower and seed descriptions with the findings of relationship studies. [Sánchez et al. 2022, p. 124–125]

In the current list, the name Escobaria strobiliformis refers to a different nomenclatural history associated with P. chihuahuensis. The similar epithet does not connect it to Encephalocarpus strobiliformis. The 2022 paper explained the former homonyms, names with the same spelling based on different material. In this account, the basionym remains Ariocarpus strobiliformis Werderm. from 1927. [Sánchez et al. 2022, p. 131–132, 141] [2-WWW]

Areoles as a source of new shoots

Pérez-Molphe-Balch and Dávila-Figueroa used both apical seedling fragments and transverse discs 4 mm thick without the apex. New shoots developed from the areoles. In Table 2, the highest result for discs in the first 60-day cycle is 12.37 ± 1.21 shoots with 4.4 µM benzyladenine and 50 g/L sucrose. After three cycles in this treatment, 119.33 ± 9.66 shoots were obtained per initial explant. [Pérez-Molphe-Balch and Dávila-Figueroa 2002, p. 75, tab. 2]

The article's abstract attributes the result of 12.37 shoots to a dose of 8.8 µM benzyladenine. Table 2 places it at 4.4 µM and gives a clearly lower result for 8.8 µM and 50 g/L. The data cited here retain the treatment given in the table. The highest number of shoots after 180 days, 136.33 ± 12.6, came from another treatment, apical fragments on 4.4 µM benzyladenine and 30 g/L sucrose. [Pérez-Molphe-Balch and Dávila-Figueroa 2002, pp. 73, 75, Table 2]

Elongation, roots and acclimatisation

Cultures grew at 25 ± 2°C, with a 16-hour day and a photon flux of 54 µmol m⁻² s⁻¹. Shoots intended for rooting were elongated first. After 60 days on medium with 3 g/L activated charcoal, their mean length was 15 ± 0.37 mm. In the MS control it was 11 ± 0.21 mm. Activated charcoal was thus an additive tested at a specific stage of culture. [Pérez-Molphe-Balch and Dávila-Figueroa 2002, p. 74, 77, tab. 3]

After six weeks, 87% of shoots had roots at least 15 mm long, pooling the treatments with the auxins used. Rooted plants were acclimatised in a 1:1 mixture of sand and soil, initially under a cover that maintained humidity. Survival after 16 weeks was 88% for the pooled material of both species in the experiment. This is a combined result for P. aselliformis and P. strobiliformis. [Pérez-Molphe-Balch and Dávila-Figueroa 2002, pp. 74, 77–78]

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