Abstract: The present papar is a report on cytotaxonomical studies of Allium Sect． Caloscordum(Liliaceae)from China． Six populations of A. neriniflorum and A．tubiflorum were introduced from Shaanxi，Hebei(Beijing)，Liaoning and Heilongjiang．Based on the introduction and cultivated experiment， the authors made a karyotype analysis and a morphological comparison of the six populations． The results are as follows． Except the population 5 (Baihuashan，Beijing)，which was found to be tetraploid 2n＝4x＝32，all the populations were dipliod 2n=2x＝16． There were two types of satellites： terminal and intercalary． The basic number，the karyotypes as well as the types of satellites in Sect． Caloscordum were the same as those in the other sections of Allium． In the populations 1， 2， 3 and 4(Daheshan，Jinxia County，Liaoning；Taikang County， Heilongjiang； Chengde to Huaqing， Hebei； Liulimao， Huairou，Beijing．)， the sixth pair of chromosomes had a pair of intercalary satellites，the mean length of pedicels is about 7 cm and the plant had no two-growth cycle．In the populations 6 (Xianyunei， Huashan， Shaanxi)： the eighth chromosome pair had a pair of terminal satellites， the pedicel was shorter，with the mean length 2．39 cm，and the plant had two-growth cycle． In the tetraploid population 5； fourteenth and sixteenth chromosome pairs both had a pair of terminal satellites，the mean length of pedicel was 2．39 cm and the plant had the two-growth cycle．According to the results，the authors keep Sect． Caloscordum in the genus Allium and recognize two species in China in the section； the populations 1， 2， 3 and 4 belong to A．neriniflorum，and the populations 5 and 6 to A．tubiflorum．Our observation on dissecting ovary showed that there were 2～11 ovules per locule；the diploid populations mainly had 5 ～6 ovules per locule，while the tetraploid ones mainly had 4 ovules per locule．Therefore， the number of ovules per locule is not a reliable character for classifiction but it may be useful in distinguishing diploid from tetraploid．However，we consider that the satellite type，the pedicel length and whether the plant has two-growth cycle are the diagnostic features for the species of Sect．Caloscordum．

Key words: Allium, Sect. Caloscordum, Karyotype, Phylogentic relationship