Selaginella moellendorffii, an important model organism for comparative genomics, belongs to an ancient vascular plant lineage, providing insights into plant evolution. With a compact 100-megabase-pair genome, it played a pivotal role in understanding the transition from gametophyte to sporophyte life cycles. Notably, Selaginella moellendorffii possesses the highest guanine + cytosine content in its organellar DNA, with 68% G+C in its mitochondrial DNA, making it an exceptional botanical specimen.