Fig. 4From: Low pyrrolizidine alkaloid levels in perennial ryegrass is associated with the absence of a homospermidine synthase geneUnrooted maximum likelihood tree of DHS and HSS amino acid sequences of various Poacae species, including Lolium perenne (Lp) and Festuca arundinacea (Fa). Bootstrap proportions resulted from 1000 replicates. Bar represents 0.02 amino acid substitutions per siteBack to article page