The paper by Hollingsworth, Graham, and Little discusses the challenges and progress in establishing a standardized DNA barcode system for plants. Unlike the successful use of the *cytochrome oxidase 1 (COI)* gene in animal barcoding, finding an appropriate barcode for plants has been more challenging due to the low rate of nucleotide substitution in plant mitochondrial genomes. The authors review the selection and refinement of a plant barcode, evaluating factors that influence its discriminatory power, and describe early applications and emerging projects. They recommend a core barcode consisting of portions of two plastid coding regions, *rbcL* and *matK*, which offer good amplification and discriminatory power. However, further work is needed to improve the amplification and sequencing of *matK* and to address the lower discriminatory power compared to *COI* in animals. The paper also discusses the use of supplementary markers and the limitations of current methods, emphasizing the need for continued research and technological advancements to enhance the effectiveness of plant DNA barcoding.The paper by Hollingsworth, Graham, and Little discusses the challenges and progress in establishing a standardized DNA barcode system for plants. Unlike the successful use of the *cytochrome oxidase 1 (COI)* gene in animal barcoding, finding an appropriate barcode for plants has been more challenging due to the low rate of nucleotide substitution in plant mitochondrial genomes. The authors review the selection and refinement of a plant barcode, evaluating factors that influence its discriminatory power, and describe early applications and emerging projects. They recommend a core barcode consisting of portions of two plastid coding regions, *rbcL* and *matK*, which offer good amplification and discriminatory power. However, further work is needed to improve the amplification and sequencing of *matK* and to address the lower discriminatory power compared to *COI* in animals. The paper also discusses the use of supplementary markers and the limitations of current methods, emphasizing the need for continued research and technological advancements to enhance the effectiveness of plant DNA barcoding.