Segments and trait distribution
Material compared in 2019 had fibrous roots and globose segments coded as spineless in the trait matrix used. Leaves were shed, and segment connections were assessed as intermediate in strength. Flowers were assigned to the pale colour group. Fruit is dry and dehiscent, with seeds in a corky covering. [Las Peñas et al. 2019, appendix 1]
The plants studied lacked the typical thickened geophyte root found in T. bonnieae and T. recurvatus. The shared ancestry of these three therefore shows that similarity of underground structure may change even within a small lineage. [Las Peñas et al. 2019]
Dwa cytotypy
Voucher specimen Las Peñas 577 was reported with 2n = 44, while specimen 288, also from Salta, had 2n = 88. At x = 11, these correspond to a tetraploid and an octoploid. The species name therefore includes material with different numbers of chromosome sets. [Las Peñas et al. 2019, Table 2]
In the chloroplast analysis, T. molinensis belonged to the same main lineage as T. bonnieae, T. recurvatus, T. nigrispinus and T. verschaffeltii. Separate comparison of stem, root and seed traits helps interpret this group, whose members differ greatly in appearance. [Las Peñas et al. 2019]
Synonyms and names in the literature
Maihueniopsis molinensis · Opuntia denudata · Opuntia molinensis · Tephrocactus molinensis var. denudatus [2-WWW]