Mosco A., Micro-morphology and anatomy of Turbinicarpus (Cactaceae) spines, Revista Mexicana de Biodiversidad, 2009, 80(1):119-128, doi: 10.22201/ib.20078706e.2009.001.589
A study of spine surfaces and internal structure in 30 species and lower-ranked taxa from a documented collection. Light and electron microscopy show differences in fibre wall thickness, tissue arrangement and epidermal cell shape. Hard, bristle-like, papery and corky spines were compared, together with the persistent feathery hairs of T. valdezianus. Functions in stem protection and water uptake are discussed as hypotheses or results of earlier studies, without direct measurements in this experiment.