At the heart of secondary growth is the cambium and its capacity to divide and generate new cells. Notwithstanding the numerous reviews of this meristem (although almost solely of the shoot cambium) over the last 80 years (reviewed in Catesson 1974, 1994; Larson 1994; Lachaud et al. 1999), there has been comparatively little new cambial cell biology (i.e., employing

molecular approaches) to review since the heyday of cambial ultrastructural studies in the 1960s and early 1970s. at contrasts markedly with the situation for the primary plant body, which in the past 30-40 years has beneted greatly from the development of new and still-emerging techniques in molecular biology (e.g., The Arabidopsis Book 2011). e application of those techniques, largely concentrated upon the “model plant” Arabidopsis thaliana (e.g., Koornneef and Meinke 2010), has generated a tremendous amount of information concerning plant development. Unfortunately, because of problems-either real or perceived-inherent in studying the cambium, particularly that of trees (see Chaey 2002c,f), there appears to have been a reluctance to pursue such investigations, and it is only relatively recently that the techniques of modern cell biology have begun to be applied to this secondary meristem (e.g., Chaey 2002a).