| Summary: | The genus <i>Crassula</i> is the second-largest genus in the family Crassulaceae, with about 200 species. As an acknowledged super-barcode, plastomes have been extensively utilized for plant evolutionary studies. Here, we first report 10 new plastomes of <i>Crassula</i>. We further focused on the structural characterizations, codon usage, aversion patterns, and evolutionary rates of plastomes. The IR junction patterns—IRb had 110 bp expansion to <i>rps19</i>—were conservative among <i>Crassula</i> species. Interestingly, we found the codon usage patterns of <i>matK</i> gene in <i>Crassula</i> species are unique among Crassulaceae species with elevated ENC values. Furthermore, subgenus <i>Crassula</i> species have specific GC-biases in the <i>matK</i> gene. In addition, the codon aversion motifs from <i>matK</i>, <i>pafI</i>, and <i>rpl22</i> contained phylogenetic implications within <i>Crassula</i>. The evolutionary rates analyses indicated all plastid genes of Crassulaceae were under the purifying selection. Among plastid genes, <i>ycf1</i> and <i>ycf2</i> were the most rapidly evolving genes, whereas <i>psaC</i> was the most conserved gene. Additionally, our phylogenetic analyses strongly supported that <i>Crassula</i> is sister to all other Crassulaceae species. Our findings will be useful for further evolutionary studies within the <i>Crassula</i> and Crassulaceae.
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