“…Many studies have addressed the morphological diversification of leaves, which often vary in size, shape, and form (e.g., Blein et al, 2008;Kimura et al, 2008;Berger et al, 2009;Piazza et al, 2010;Yamaguchi et al, 2010). While often more conservative than leaves, extensive morphological diversity is also seen in stems, most dramatically with the production of tendrils, thorns, and flattened, leaf-like stems (Bell, 2008).…”