Arisaema species from Shikoku Island, Japan

Arisaema species in Japan exhibit extensive morphological variation that has complicated their taxonomy, particularly the debated distinction between Arisaema japonicum and A. serratum. To assess whether A. japonicum represents a distinct lineage or falls within the natural variation of A. serratum, we generated a genomic dataset using genotyping-by-sequencing (GBS). Fresh leaf tissue was collected from 13 individuals representing four morphotypes (n = 7 A. serratum; n = 6 A. japonicum) across five sites on Shikoku Island, Japan, spanning elevational and ecological gradients. Libraries were prepared with ApeKI digestion and sequenced on an Illumina NovaSeq 6000 platform. Reads were quality-filtered, aligned to the draft genome of A. tosaense, and processed to call genome-wide SNPs. Subsequent analyses revealed no reciprocal monophyly between A. japonicum and A. serratum, with individuals instead clustering by geography. This dataset therefore, provides a robust genomic resource for testing species boundaries in the A. serratum complex and offers a foundation for future studies of hybridization, phylogeography, and morphological variation in Arisaema