sentence: Researchers have been using herbarium specimens in molecular phylogeny studies and consider them as an interesting potential source of material for DNA barcoding and the construction of a barcode library for flora ( Cozzolino et al ., 2007 ; Erkens et al ., 2008 ; Tarieiev et al ., 2011 ; de Vere et al ., 2012 ; S ä rkinen et al ., 2012 ; Hebert et al ., 2013 ; Xu et al ., 2015 ; Bakker , 2017 ) .