The evolution of community characteristics and biological characteristics of plant is always one of the core problems in the field of community ecology and reproductive ecology.The significance and protection work of psammophytes ephemeral plant under special ecosystem have caused the entensive concern in recent years.With the ability of contributing to maintain desert stabilization,Hypecoum erectum,as a kind of psammophytes ephemeral plant,mainly distributed in the Junggar Desert and completed the whole growth in the spring spending only two months.We did our research in wild populations in the south edge of Gurbantunggut desert,Xinjiang,China.Using the method of sampling survey to investigate the community characteristics and the flower bio-ecological characteristics of 8 populations,the results indicated that:(1)the average height of the H.erectum plants is (13.54±1.24) cm,crown of east-west and south-north is (15.50±1.81) cm and (14.53±1.75) cm,respectively.The seed of H.erectum is small with the thousand seed weight (0.291 0±0.002 7) g,flowering phase last nearly fifty days from late April to early June,as to the fruiting phase cost nearly two months from mid May to early July,which shows no obvious difference between 2013 and 2014.Thirty species were recorded from the natural communities of H.erectum,which belong to 28 genus of 15 families,during which the family of single specie and genera of single specie amount a lot,showing a distinct flora dominance.Compositae,Chenopodiaceae and Cruciferae were the dominant families accounting for 23.3%,13.3% and 10.0%,respectively.There is a big diversity of the live form with only one species in tree layer,three species in brushwood layer and twenty-six species in herb layer.The floral element analysis of genus indicated that the Mediterranean element and West Asia to Mid Asia element account for the large part of the H.erectum community,which has the typical flora of Mediterranean xerophyte characteristics.(2)According to the community constitution and important value,the 8 populations can be divided into three associations,the first is H.erectum+Poa pratensis+Seriphidium terrae-albae,the second is H.erectum+Calligonum ebinuricum+Seriphidium terrae-albae and the third is H.erectum+Seriphidium terrae-albae+Ephedra distachya.(3)We chose the 3th sample from 8 population to observe the floral characteristics,results showed that the flowering span of the population,individual,inflorescence and single flowering were approximately 37-40 d,14-16 d,13-15 d and 1-2 d,respectively.The life span of single flower would prolong 2 d when overcast and rain occurred.This floral trait is an adaptive exhibition to desert environment.H.erectum has elaborate floral characteristics.The middle lobe on the two inner petals is specialized as a yellow cucullate structure.The middle lobe will reflexively wrap the anther as soon as the anther dehiscence,obtaining pollen and growing upward.The cucullate structure is the key function organ in stamen mimicry and secondary pollen presentation.By researching the characteristics of floral of H.erectum,a theoretical basis can be provided to explore the pollination adaptability and breeding system characteristics.