“…Cactaceae are some of the most remarkable organisms in the plant kingdom, with numerous unique features, such as a delayed formation of a periderm, the evolution of medullary bundles, and leaves modified into spines (summarized by Mauseth [2006] and Edwards and Donoghue [2006]). There are three distinct Cactaceae wood types (Mauseth and Plemons, 1995): (1) fibrous wood marked by the presence of vessels, fibers, scanty vasicentric parenchyma and sometimes bands of nonlignified parenchyma (Figure 9A); (2) wide‐banded tracheids (WBT) wood, composed of WBTs and parenchyma (Figure 9B, C); and (3) parenchymatous wood, characterized by vessels and abundant nonlignified parenchyma (Gibson, 1973; Mauseth and Plemons, 1995; Landrum, 2002; Terrazas and Arias, 2003; Mauseth, 2004; Soffiatti and Angyalossy, 2005, 2007, 2009). A complete phylogenetic reconstruction of wood evolution of Cactaceae is yet to be done; therefore, we here discuss major transitions in wood anatomy in the context of the currently available wood anatomy and phylogenetic literature (Hernández‐Hernández et al, 2011; Vázquez‐Sánchez et al, 2013; Guerrero et al, 2019; Martínez‐Quezada et al, 2020).…”