Abstract:

Ephemeral plants are a specialized group derived from arid flora and grow in flat desert regions. In China， they are primarily distributed in northern Xinjiang， while the overall distribution status in southern Xinjiang remains unclear. Moreover， it is currently unknown whether ephemeral plants exist in alpine environment. Combined the field surveys with literature review， the species composition and geographical elements and life-form types of ephemeral plants in northern Xinjiang， southern Xinjiang （including the Pamir Plateau within China） were analyzed respectively， and their origins and life-history strategy differentiation were explored. The results showed that： （1）There were 18 families， 42 genera and 51 species ephemeral plants in southern Xinjiang； the Pamir Plateau within China had 16 families， 31 genera and 36 species ephemeral plants， which served as a “micro-refugium”. （2）The proportion of oligotypic families， monotypic families， oligotypic genera and monotypic genera in Xinjiang was high， and Brassicaceae was the dominant family. （3）The ephemeral plants in Xinjiang were predominantly temperate ones， with a high proportion of annual and perennial life forms. The proportion of annual plants in alpine environments increased， which highlighted the constraining effect of ecological conservation on the evolution of ephemeral plants. In summary， the ephemeral flora of northern and southern Xinjiang showed significant convergence in terms of family and genus composition， geographical elements and life-form spectrum， the Pamir Plateau within China served as a “micro-refugium” for ephemeral plants， and their ecological conservation subjected them to considerable evolutionary pressure.

Key words: short growth period, species composition, geographical elements, life form, life-history strategy