Abstract:Aims Flowering phenology is considered as an important fitness factor because it plays a crucial role in reproductive success. Our aim is to investigate the flowering phenology of Eremosparton songoricum, the 3rd Class national protected dwarf shrub with a fragmented distribution in Gurrbantuggut Desert of Xinjiang, China, to better understand its reproductive features. Methods We marked and observed 30 E. songoricum individuals with similar heights and crown diameters in the wild population of Cainan Oil Station in Gurrbantuggut Desert from 2005 to 2006. We observed the flowering course of each individual and inflorescence including the first flowering date, duration, mean flowering amplitude (flowers plant–1·d–1) and last flowering date and then calculated relative flowering intensity and synchrony indices. We also analyzed relationships between first flowering date, median date, duration, last flowering date, flowering amplitude and flowering synchrony, the correlation matrix between first flowering date and duration, flower number and fruit set. Important findings The flowering span of the population, individual, inflorescence and single flowering was approximately 26-29, 8-10, 5-7 and 2-3 d, respectively. None of the phenology index levels between 2005 and 2006 were distinctive. The synchrony index was 0.829. The relative flowering intensity showed one major peak from 10% to 30% and the skewness was 1.24. According to flower morphology and dehiscence, the typical single flowering process for a flower can be divided into four periods: pre-dehiscence, initial dehiscence, full dehiscence and withering. The correlation analysis among the first flowering date, duration, flower number and fruit number shows that 1) there is negative correlation between first flowering date and duration and a positive correlation to flower number and fruit number, 2) duration has a significant positive correlation to flower number and fruit number and 3) there is significant positive correlation between flower number and fruit number. Individuals with more flowers show a longer duration and more fruit than these with fewer flowers. As a rare plant in China’s desert zone, E. songoricum exhibits a so-called “mass-flowering” pattern, which may be regarded as an adaptive strategy to ensure its reproductive success.