With the recent proposal of matK and rbcL as core plant DNA barcoding regions by the Consortium for the Barcoding of Life Plant Working Group, the construction of reference libraries in the botanical DNA barcoding initiative has entered a new phase. However, in a recent DNA barcoding study in the three Mexican genera of the gymnosperm order Cycadales, we found that neither matK nor rbcL allow high levels of molecular identification of previously established species.
Nicolalde-Morejón, F., Vergara-Silva, F., González-Astorga, J., & Stevenson, D. W. (2010). Character-based, population-level DNA barcoding in Mexican species of Zamia L. (Zamiaceae: Cycadales). Mitochondrial DNA, 21(SUPPL. 1), 51–59. https://doi.org/10.3109/19401736.2010.539215