Řepka R., Gebauer R., Micromorphological and anatomical spine features of selected Escobaria species (Cactaceae), Bradleya, 2012, 30:138-146, doi: 10.25223/brad.n30.2012.a16
A comparison of spine surfaces and anatomy in five historically distinguished Escobaria taxa. Material comes from three areoles of cultivated plants of known origin. The authors describe epidermal hairs, cross-sectional structure and cell dimensions, and compare them with stem, flower and seed morphology. Four tissue zones in Escobaria abdita spines and hairs in two Escobaria missouriensis samples are the main differentiating traits.