Marchantia polymorpha has 9 chromosomes and a genome size of around 290MB. The dominant form is the haploid gametophyte. The plant is dioecious, with sex determined by segregating X and Y chromosomes. The Y chromosome has been sequenced recently (Yamato et al. (2007) Gene organization of the liverwort Y chromosome reveals distinct sex chromosome evolution in a haploid system). The M. polymorpha genome is being sequenced currently by a consortium led by Takayuki Kochi and John Bowman. The entire chloroplast and mitochondria genome sequences have been determined (Reviewed in Ohyama et al. (2009) Gene content, organization and molecular evolution of plant organellar genomes and sex chromosomes: insights from the case of the liverwort Marchantia polymorpha).
Above, from Ono (1976) Cytological observations on the calluses and the restored thalluses in Marchantia polymorpha. Japan. J. Genetics 51:11-18.
Plastid gene maps from Ohyama et al. (2009) Gene content, organization and molecular evolution of plant organellar genomes and sex chromosomes: insights from the case of the liverwort Marchantia polymorpha.