The complete chloroplast genome sequence and phylogenetic analysis of <i>Hordeum pusillum</i> Nutt., 1818 (Poaceae)

<i>Hordeum pusillum</i> (<i>Hordeum pusillum</i> Nutt., 1818) is an annual barley that is native to the west of the North America and widespread in southern United States and tropical America. In this study, we have provided the first complete characterization of the chloroplast genome of <i>H. pusillum</i>. Our research revealed that the circular chloroplast genome of <i>H. pusillum</i> consists of a large single-copy region (LSC: 80,853 bp), a small single-copy region (SSC: 12,745 bp), and a pair of inverted repeat regions (IRs: 21,587 bp), totaling 136,772 bp in length. Within the chloroplast genome of <i>H. pusillum</i>, 91 protein-coding genes, 38 tRNA genes, and ten rRNA genes were identified. To determine the evolutionary relationship of <i>Hordeum</i> species with reported chloroplast genome sequences, we constructed a phylogenetic tree using the entire chloroplast genome sequences. The evolutionary position of <i>H. pusillum</i> corresponds to its geographical location. The chloroplast genome of <i>H. pusillum</i> provided in this study may have significant implications for the phylogenetic study of Poaceae species.