Fig. 2From: Variability in ITS1 and ITS2 sequences of historic herbaria and extant (fresh) Phalaris species (Poaceae)a Scatter plot and linear regression of the relationship between DNA concentration (ng/μL) and sample age among herbarium specimens (orange) of Phalaris species ordered by relative age (collection year from 1882 to 2001). b Extant (fresh) samples harvested on June 17th, 2019; linear regression was not performed due to small sample sizeBack to article page