Abstract:In order to explore the karyotype and genome size of Daemonorops jenkinsiana, the root and stem tips from its seedlings were used as experimental materials. The karyotype of D. jenkinsiana, including chromosome number and morphology were analyzed by combining the conventional method of somatic cell chromosome preparation with microphotography. Meanwhile, the DNA content, genome size and ploidy of leaves were determined by flow cytometry using Lycopersicon esculentum as an internal reference. The results showed that the stem tip of D. jenkinsiana was an ideal material for chromosome preparation, and the chromosome number was 2n=24, along with the formula of karyotype was K(2n)=1M+17m+5sm+1st, and the karyotype was "2C". The karyotype asymmetry index of D. jenkinsiana was 61.20%. The DNA content of D. jenkinsiana was about 1.57 pg with the genome size of 1 535.53 Mb, and the DNA ploidy was diploid (2n). This was reported the karyotype and genome size of D. jenkinsiana for the first time, which provided a reference for studying the karyotype and genome of other species in Daemonorops and related genus.