A genome assembly for the California endemic liverwort Calasterella californica

Calasterella californica belongs to a monotypic genus of liverworts endemic to the west coast of North America, primarily distributed in California. This dioicous species occurs in a variety of ecosystems from deserts to redwood forests; little is known about how this species is adapted to live in those seemingly contrasting environments. In this paper, we report on the assembly of the nuclear genome of C. californica. As part of the California Conservation Genomics Project (CCGP), we used Pacific Biosciences HiFi long-read sequencing data to produce a de novo assembly that consists of 772 contigs, with a total length of 517 Mbp and a BUSCO complete score of 95%. Calasterella californica is only the sixth species of liverworts-a group with more than 7,200 described species-to have a nuclear reference genome. The availability of this reference genome will facilitate the study of the unique features of C. californica and other liverworts, pave the road towards a comparative understanding of liverwort genomes, and add an important starting point for studies of the geographic variation of this species within the CCGP project.