The reconstruction of ancestral chromosome karyotypes can provide important references for revealing the chromosomal evolutionary trajectory of existing species (Pont et al., 2019). Assuming that the 7 chromosomes in the karyotype of ancestral eudicots are G1-G7, and the 21 chromosomes after ECH are A1-A7, B1-B7, and C1-C7. After the merger of four chromosomes, 17 chromosomes of the ancestor of Cucurbita were formed, and after a diploidy shared by Cucurbita (CCT), two more chromosomes were fused to form ACK-II. Then, 17 chromosomes merged to form the 15-chromosome ancestor of Cucurbitaceae. The Cucumis ancestor was formed by the fusion of 15 chromosomes of Cucurbitaceae with 1 chromosome, which underwent another diploidy (CST). Begoniaceae consists of 32 chromosomes fused with 18 chromosomes, and then fused with 11 chromosomes after specific diploidy (BCT) to form the ancestor of Begoniaceae