• In the News & Views article “Plant biology: Auxin action” by Judy Callis (Nature 435, 436–437; 200510.1038/435436b), editorial error introduced the implication that auxins are proteins. They are not. Naturally occurring auxins are low-molecular-weight compounds derived from the amino-acid tryptophan or a tryptophan precursor.

• In “Organic chemistry: Fast reactions ‘on water’” by Jaap E. Klijn and Jan B. F. N. Engberts (Nature 435, 746–747; 2005), the page numbers for the main paper under discussion (ref. 2) were wrong in the print edition. The correct reference, which appears in the online edition, is Narayan, S. et al. Angew. Chem. Int. Edn 44, 3275–3279 (2005).