Pterocactus hickenii

Segment appearance

The segment surface is grey-brown and tuberculate, and areoles lack dense woolly hairs. In the morphological comparison, central spines are cylindrical and about 10–20 mm long. The flower is terminal. The underground system sustains the plant between successive periods of above-ground development. [Las Peñas and Bernardello 2021, Table 2]

The epidermis has straight papillae with distinctly striated bases. The cuticle between them is relatively smooth. Internal anther structure follows the arrangement also described in three other Pterocactus, and mature pollen is bicellular and multiporate. [Faigón et al. 2011] [Gotelli et al. 2009]

Southern range and genome

The species occurs in Argentina and Chile. In the 2021 chloroplast analysis, it grouped with P. araucanus in one of the genus's main lineages, with P. neuquensis separating earlier. This group is strongly associated with southern areas of Pterocactus diversification. [Las Peñas and Bernardello 2021]

A direct count gave 2n = 154. At x = 11, this means a fourteen-fold level. DNA content was 16.68 pg at the 2C level. Both parameters concern particular cytogenetic material. [Las Peñas and Bernardello 2021, Table 1]

Pollen with numerous pores

Compared with P. araucanus, P. australis and P. valentini, pollen of P. hickenii had the greatest number of pores. The outer wall forms a finely perforated surface with spines. Pollen traits supplement the species' external description, but the study did not use them to determine practical pollination effectiveness. [Gotelli et al. 2009]