The organisers of the 9th John Innes Symposium, who were beginning to plan their programme around the theme of plant development, and in particular, on pattern formation, were delighted when the British Society for Developmental Biology suggested a joint meeting with them. This enabled the full range of biological pattern formation to be addressed, with talks including work on both plant and animal systems. Unusually for a meeting of this kind, there was a slight bias in favour of the number of plant speakers, but this helped to focus our attention on two themes that ran through the meeting. The first was the emergence of a number of underlying molecular mechanisms and strategies in development, perhaps better publicised in animal systems, that are also held in common with plants, for example, cell polarity, homeotic selector genes. In contrast to this was the clear message that there are also developmental strategies that are rather specific to plants, for example, the great importance of division plane alignment, the establishment of meristems, and enormous developmental plasticity. The meeting was an ideal opportunity to hear about the rapid progress that is being made through the application of molecular genetics, and to make connections from either side of the green-red divide between the emerging molecular models that underlie pattern formation in a very wide range of organisms.

The organisers of the 9th John Innes Symposium, who were beginning to plan their programme around the theme of plant development, and in particular, on pattern formation, were delighted when the British Society for Developmental Biology suggested a joint meeting with them. This enabled the full range of biological pattern formation to be addressed, with talks including work on both plant and animal systems. Unusually for a meeting of this kind, there was a slight bias in favour of the number of plant speakers, but this helped to focus our attention on two themes that ran through the meeting. The first was the emergence of a number of underlying molecular mechanisms and strategies in development, perhaps better publicised in animal systems, that are also held in common with plants, for example, cell polarity, homeotic selector genes. In contrast to this was the clear message that there are also developmental strategies that are rather specific to plants, for example, the great importance of division plane alignment, the establishment of meristems, and enormous developmental plasticity. The meeting was an ideal opportunity to hear about the rapid progress that is being made through the application of molecular genetics, and to make connections from either side of the green-red divide between the emerging molecular models that underlie pattern formation in a very wide range of organisms.

We were particularly fortunate to hear Professor Nüsslein-Volhard deliver the Bateson Memorial Lecture at the beginning of the meeting, on how a coarsegrained spatial framework is established, through a small number of longitudinal and transverse domains in the early Drosophila embryo, that becomes progressively refined by the action and interaction of zygotic pattern genes. This provided an invaluable reference point throughout the meeting and I believe the high quality and breadth of the contributions that followed is accurately reflected in the papers collected here. We are grateful to the Company of Biologists for their help and enthusiasm in transforming the meeting into a Supplement to the journal Development.