UNLABELLED PREMISE OF THE STUDY Secondary metabolites often inhibit PCR and sequencing reactions in extractions from plant material, especially from silica-dried and herbarium material. A DNA polymerase that is tolerant to inhibitors improves PCR results. • METHODS AND RESULTS A novel DNA amplification system, including a DNA polymerase engineered via directed evolution for improved tolerance to common plant-derived PCR inhibitors, was evaluated and PCR parameters optimized for three species. An additional 31 species were then tested with the engineered enzyme and optimized protocol, as well as with regular Taq polymerase. • CONCLUSIONS PCR products and high-quality sequence data were obtained for 96% of samples for rbcL and 79% for matK, compared to 29% and 21% with regular Taq polymerase.