The complete plastid genome of Crepidium calophyllum (Orchidaceae: Malaxidinae) and phylogenetic analysis.

Crepidium calophyllum is a terrestrial orchid native to tropical forests in southern China and Southeast Asia. Once classified under Malaxis, it has since been reassigned to Crepidium. This study presents the first complete plastid genome (plastome) of C. calophyllum, which is 158,884 bp in length. Its gene content and order are highly conserved compared to other autotrophic species within Malaxidinae. Phylogenomic analyses using both maximum likelihood and Bayesian inference, based on complete plastomes, place C. calophyllum within Crepidium, as sister to Dienia. Interestingly, these analyses also reveal the polyphyly of Malaxis and Liparis, suggesting unresolved taxonomic issues within Malaxidinae.