Pterocactus reticulatus

Pterocactus reticulatus

Pterocactus reticulatus R.Kiesling

A species of Mendoza and San Juan, with tuberculate segments, woolly areoles and lateral flowers. In the chloroplast analysis it belongs to a different main lineage from Pterocactus neuquensis, which also flowers laterally. [Las Peñas and Bernardello 2021] [2-WWW]

1 min readAccount dated 9 October 2026

Structure and flower position

Segments are globose or obovoid and brown-purple. Areoles with woolly hairs stand out between the tubercles. Cylindrical central spines are about 2–5 mm long in the species comparison. The flower is lateral. [Las Peñas and Bernardello 2021, Table 2]

Lateral flowering also occurs in P. neuquensis, but DNA analysis did not place these species in one exclusive group. P. reticulatus belonged to the lineage containing P. fischeri, P. valentini and P. tuberosus. The flower trait is therefore interpreted alongside other traits and the history of the genus. [Las Peñas and Bernardello 2021]

Surface under the microscope

The epidermis has straight papillae. Their bases are distinctly striated and their tips smooth. The cuticle between them has a relatively smooth surface. Preparations also revealed stomata with subsidiary cells typical of the Pterocactus group studied. [Faigón et al. 2011]

Stanowiska dokumentacyjne

The specimens studied came from Mendoza and San Juan. The 2021 cytogenetic table gave neither chromosome number nor genome size for P. reticulatus. Its position in the comparison followed from chloroplast and morphological data. [Las Peñas and Bernardello 2021]

Sources for this account

Article2021

Divergence time estimation and mapping of morphological and cytogenetical data in the southern South American geophyte genus Pterocactus (Cactaceae)

Las Peñas M. L., Bernardello G., Divergence time estimation and mapping of morphological and cytogenetical data in the southern South American geophyte genus Pterocactus (Cactaceae), Taxon, 2021, 70(3):552-569, doi: 10.1002/tax.12497

A phylogeny of ten Pterocactus species recognised at the time, based on three chloroplast markers. The paper brings together stem and spine structure, flower position, chromosome numbers and DNA content. It also includes a model-based estimate of the timing of diversification in the genus.

Physiology and anatomyGenusPterocactus

DOI ↗Article or source page ↗

[2-WWW]Source website

Plants of the World Online — Royal Botanic Gardens, Kew

https://powo.science.kew.org/

Accepted names, synonyms and distribution. A citation beside a taxon leads to its record.

Accessed 2026-10-08.

Article2011

Epidermal characters of Pterocactus (Opuntioideae, Cactaceae)

Faigón A., Galati B. G., Rosenfeldt S., Kiesling R., Epidermal characters of Pterocactus (Opuntioideae, Cactaceae), Haseltonia, 2011, 16(1):57-66, doi: 10.2985/1070-0048-16.1.57

A microscopic comparison of the epidermis in eight Pterocactus species. It includes descriptions of stomata, papillae on epidermal cells, cuticular sculpture and wax distribution. The authors discuss the value of these traits in distinguishing similar species.

Physiology and anatomyGenusPterocactus

DOI ↗Article or source page ↗