Morphological variation and haplotype diversity of \(\textit{Halimeda macroloba}\) and \(\textit{H. opuntia}\) (Chlorophyta: Halimedaceae) from Southern Vietnam

Plasticity in morphology is a common phenomenon of aquatic plants. Halimeda (Chlorophyta: Halimedaceae) usually supersaturated with calcium carbonate and found tropical subtropical regions. Among members Halimeda, both species including macroloba H. opuntia, often occur different habitats. Haplotype diversity network were reported the sea oceanic systems. However, there are no reports genetic Vietnamese waters. This present study carried out sample collections along coast Southern Viet Nam, sites, offshore islands, Spratly (Truong Sa) islands. External morphological anatomical characteristics two dominant species, caparisoned. The marker tufA was applied to find haplotype among worldwide populations. results showed that high exists species. In contrast, variation very low, opuntia tends form distinct group. We suggest more samples from other locations Northern Vietnam be included.