The complete chloroplast genome of the salt-tolerant plant Kalidium caspicum (Amaranthaceae) and evolutionary relationships.

Kalidium caspicum belongs to the genus Kalidium (Amaranthaceae). We assembled and annotated its chloroplast genome for the first time. The chloroplast genome exhibits a circular quadripartite structure, with a total length of 153,693 bp and a GC content of 36.3%. It contains 130 genes, including 85 protein-coding genes, 37 tRNA genes, and eight rRNA genes. Phylogenetic analysis consistently recovered K. caspicum, K. foliatum, and K. gracile, Salicornia bigelovii, and S. fruticosa as a well‑supported clade. This study clarifies the chloroplast genome characteristics and phylogenetic position of K. caspicum, providing a basis for molecular identification and phylogenetic research in Kalidium.