Segments and surface
Segments are light brown to grey and tuberculate, with conspicuously hairy areoles. The cylindrical central spine measures about 2 mm in the material compared in the molecular monograph. The flower develops terminally. [Las Peñas and Bernardello 2021, Table 2]
Epidermal papillae are curved. Their bases have weaker striations than in P. araucanus or P. gonjianii. The cuticle on ordinary cells has delicate, irregular striations. The characterisation was based on preparations examined with light and scanning electron microscopes. [Faigón et al. 2011]
San Juan and placement in the genus
The 2021 account classifies P. megliolii as endemic to San Juan. In the chloroplast tree it belongs to the lineage also containing P. gonjianii and P. tuberosus. Relationships were compared with similarity of cylindrical segments and stem-surface traits. [Las Peñas and Bernardello 2021]
DNA content at the 2C level was 4.94 pg. On this basis, the authors estimated a diploid level corresponding to 2n = 22. Unlike results for P. gonjianii and P. hickenii, the number for P. megliolii in this table was inferred from cytometry without direct counting. [Las Peñas and Bernardello 2021, Table 1]
Synonyms and names in the literature
Opuntia megliolii [2-WWW]