Vázquez-Sánchez M., Terrazas T., Arias S., Morfología y anatomía del cefalio de Cephalocereus senilis (Cactaceae), Anales del Jardín Botánico de Madrid, 2005, 62(2):153-161, doi: 10.3989/ajbm.2005.v62.i2.16
A comparison of young shoots and the reproductive region of Cephalocereus senilis connects external morphology with anatomy. Enlarged areoles, dense indumentum, early periderm formation and loss of chloroplasts characterize the lateral cephalium. The material came from the Metztitlán reserve in Hidalgo.