A molecular and morphological investigation of Batrachospermum arcuatum (Batrachospermales, Rhodophyta) in China

Batrachospermum arcuatum specimens were analysed from seven stream segments in North China. Morphological characteristics were observed and cluster analysis was used to evaluate the divergence among thalli from. Sequence data of the rbcL gene (chloroplast gene) and cox2-3 spacer region (mitochondrial gene) were also utilized to evaluate genetic variation in specimens among stream segments. The specimens from four of the streams were monoecious, while the individuals at the other three locations were dioecious. Cluster analysis showed that the monoecious specimens were not separated from the dioecious specimens, based on morphology, but rather the specimens were grouped by geographical closeness and habitat similarity. Likewise, the combined analyses of rbcL and the cox2-3 spacer data from provided more evidence that breeding system (monoecy vs. dioecy) is not a good morphological character to distinguish species.