The complete chloroplast genome of Syzygium acuminatissimum.

Syzygium acuminatissimum is a valuable hard wood species in southern China. In this study, we sequenced, assembled and annotated the complete chloroplast genome of S. acuminatissimum. The complete cp genome of S. acuminatissimum was 159,352 bp in length, with a total of 109 unique annotated genes, including 78 protein-coding genes, 27 tRNA genes and 4 rRNA genes. Phylogenetic analysis showed that S. acuminatissimum was closely related to its congener S. aromaticum.

Lectotypification of the name Melastoma candidum f. albiflorum and its taxonomic status.

A nomenclatural and taxonomic treatment of the name Melastoma candidum f. albiflorum (Melastomataceae) is presented. A lectotype is designated for this name, with an updated morphological description based on fresh material. The name Melastoma candidum f. albiflorum is proposed as a heterotypic synonym of Melastoma candidum.

Molecular identification of natural hybridization between Melastoma malabathricum and Melastoama beccarianum in Sarawak, Malaysia.

Hybridization is very common in flowering plants and it plays a significant role in plant evolution and adaptation. Melastoma L. (Melastomataceae) comprises about 80-90 species in tropical Asia and Oceania, among which 41 species occur in Borneo. Natural hybridization is frequently reported in Melastoma in China, but so far there have been no confirmed cases of hybridization in Southeast Asia (including Borneo), where most species occur. Here, we identified a case of natural hybridization between Melastoma malabathricum L. and Melastoma beccarianum Cogn. in Sarawak, Malaysia, by using sequence data of three nuclear genes and one chloroplast intergenic spacer. Melastoma malabathricum is the most widespread species of this genus, occurring in almost the whole range of this genus, while M. beccarianum is a local species endemic to northern Borneo. Our results showed that natural hybridization and introgression occur between M. malabathricum and M. beccarianum, and the introgression was asymmetrical, mainly from M. malabathricum to M. beccarianum. As adaptive traits can be transferred by introgression, our study suggests that natural hybridization should be a significant mechanism for the evolution and adaptation of Melastoma in Southeast Asia. However, introgression from the common species M. malabathricum to the relatively rare species M. beccarianum may cause the decline of M. beccarianum, incurring conservation concern. With a large number of species of Melastoma and almost year-around flowering in Southeast Asia, more cases of natural hybridization are expected to be found and identified in near future.