On the cover: In the liverwort Marchantia polymorpha, male and female sexual branches exhibit a conspicuous morphological difference, yet the cell-level patterning processes governing the formation of this sexual dimorphism remain largely unknown. Cui et al. now disclose that the primordia of male and female sexual branches exhibit an overall similar morphology in early stages, yet they are already differentiated in terms of the spatial distribution patterns of cell division and elongation, as well as the disposition of germline precursors that subsequently develop into the sex-specific spatial arrangement of sperm- and egg-containing reproductive organs (gametangia).

The cover image illustrates the cell segmentation output of a 3-D confocal image of a female primordium using the MorphoGraphX program.

Image credit: Yihui Cui (Nara Institute of Science and Technology, Japan).