Expected rearrangements in the evolution of fern cp genomes. Genes are represented by boxes extending right or left of the base-line according to the direction of transcription. Each colored gene segment shows the same gene order region among the seven land plants cp genomes. The boxes highlighted in red denote the inversion of trnD-GUC. Excluding Alsophila spinulosa, the unchanged tRNA anti-codon is abbreviated in the other six cp genomes. The genes that are missing in one or more cp genomes are shown in purple. The tRNA-leu (CAA/UAA) gene between rps4 and ndhJ is indicated in bold italic type. The pseudogene is denoted by ψ. A, details are shown in the following Figure 5; B, hypothetical pathways to explain this rearrangement are illustrated in the following Figure 6.