A plastome is the genome of a plastid, a type of organelle found in plants and in a variety of protoctists. The number of known plastid genome sequences grew rapidly in the first decade of the twenty-first century. For example, 25 chloroplast genomes were sequenced for one molecular phylogenetic study. The flowering plants are especially well represented in complete chloroplast genomes. As of January, 2017, all of their orders are represented except Commelinales, Picramniales, Huerteales, Escalloniales, Bruniales, and Paracryphiales.