Abstract: Abstract: Objective In order to certain the ploidy in Eulaliopsis binata, chromosome squash method that dealt with two different conditions: enzyme and acid, had been launched to identify the number and Karyotype of chromosome. Method Using the chromosome squash method, the chromosomes in Eulaliopsis binata were distinguished under light microscope. Then those pictures were measured by Simple PCI Image Analysis software and LUCIA Cytogenetics Chromosome Image Analysis to determine the Karyotype. Results These results demonstrate the chromosomes in Eulaliopsis binata is 40, and its Karyotype could be formulated as 2n＝40＝18m+2sm ,belonging to Stebbins’s 1B type.The meiosis in Eulaliopsis binata undergoes continued cytokinisis, and at matephase appears 20 bivalents. Also, in this study, some abnormal phenomena were observed: at metaphase I, some chromosome appeared unpaired with a 34.3% frequency; one or three lagged chromosomes at anaphase I with a 32.4% frequency; and during the tetrad period, one microkernel in 20 cells was approximately distinguished Conclusions Eulaliopsis binata is a polyploid species with 40 chromosomes and is expected to be heterotetraploid, based on the Karyotype analysis and the chromosome behaviors during the meiosis.

Key words: Eulaliopsis binata, chromosome, karyotype, meiosis, heterotetraploid