Mature stem anatomy
In the comparison of four species, Selenicereus atropilosus had a greater proportion of palisade parenchyma in the stem cortex. This tissue lay beneath the hypodermis, with storage parenchyma closer to the vascular cylinder. In the studied material, the cuticle was the thickest and guard cells were the longest among the species compared. [Martínez-Quezada et al. 2019, pp.3–4,7–9, Table6]
Material and diagnostic significance
Martínez-Quezada and colleagues compared 25 anatomical characters in four species. Samples came from plants collected in the wild and maintained in the UNAM collection. Material represented three localities for each of three species and one for S. murrillii. Measurements concerned middle segments of mature stems. [Martínez-Quezada et al. 2019, pp.2–3, Table1]
The combination of epidermal and hypodermal characters differentiated groups within the analysed dataset. The authors also note the plasticity of some of these structures and the need for further comparison. An individual cuticle thickness or stomatal count needs to be considered in relation to the material, sampling position and growth conditions. [Martínez-Quezada et al. 2019, pp.8–10]