1. Mounting a fundamental defence of the plant kingdom Stephen Blackmore and Sara Oldfield; 2. Using DNA sequence data to enhance understanding and conservation of plant diversity at the species level Peter M. Hollingsworth, Linda Neaves and Alex D. Twyford; 3. Conservation assessments and understanding the impacts of threats on plant biodiversity Malin Rivers; 4. The role of botanic gardens in in situ conservation Jin Chen, Richard Corlett and Charles Cannon; 5. The role of botanic gardens in ex situ conservation Paul Smith and Valerie Pence; 6. The role of botanic gardens and arboreta in restoring plants: from populations to ecosystems Kayri Havens; 7. Botanic gardens and solutions to global challenges Samuel F. Brockington and Beverley J. Glover; 8. Cultivating the power of plants to sustain and enrich life: how public gardens can realise our purpose by focusing on the basic human needs universal to diverse audiences Sophia Shaw and Jennifer Schwarz-Ballard; 9. Botanic gardens and conservation impact: options for evaluation Val Kapos and Sara Oldfield; 10. Conclusions Stephen Blackmore, Sara Oldfield and Paul Smith.