Evolution of development of vascular cambia and secondary growth

Summary Secondary growth from vascular cambia results in radial, woody growth of stems. The innovation of secondary vascular development during plant evolution allowed the production of novel plant forms ranging from massive forest trees to flexible, woody lianas. We present examples of the extensive phylogenetic variation in secondary vascular growth and discuss current knowledge of genes that regulate the development of vascular cambia and woody tissues. From these foundations, we propose strategies for genomics‐based research in the evolution of development, which is a next logical step in the study of secondary growth. Contents Summary 577 I. Introduction 577 II. Generalized function of vascular cambia and their developmental and evolutionary origins 578 III. Variation in secondary vascular growth in angiosperms 581 IV. Genes and mechanisms regulating secondary vascular growth and their evolutionary origins 584 V. Evolution of development approaches for the study of secondary vascular growth 587 VI. Conclusions 589 Acknowledgements 589 References 589