2.4 Phylogenetic analysis
The chloroplast genomes of the eight species of Chinese Cyatheaceae were compared globally, and the phylogenetic trees were constructed with four methods (ML, BI, MP, and NJ) using Cibotium barometz (Linn.) J. Sm. as an outgroup, as shown in Figure 2. The topologies of the four trees were consistent, except that the support rate of the branches of the Alsophila denticulata and Alsophila gigantea was lower (the bootstrap values of ML, MP, and NJ were 55%, 59.2%, 99%, respectively, and the posterior probability of BI was 0.935). The support rate of the other branches was higher (the bootstrap values of ML, MP, and NJ were all 100%, and the posterior probability of BI was 1.00). Closely related Sphaeropteris brunoniana andSphaeropteris lepifera were clustered into one branch, which was located at the base of the phylogenetic tree. That means they were an earlier-diverged group in this family. Alsophila denticulata ,Alsophila podophylla , Alsophila gigantea , andAlsophila metteniana were clustered into one branch, which was located inside the branch of Sphaeropteris brunoniana andSphaeropteris lepifera and was a sister group of the branch formed by Alsophila spinulosa and Alsophila costularis .