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Halostachys caspica (Chenopodiaceae) is a halophytic shrub commonly found in saline areas of the western deserts in China that produces small-sized seeds (0.07 mg). Effects of temperature, light, NaCl, and polyethylene glycol-6000 on seed germination were investigated by incubating seeds in Petri dishes in controlled environments. Seed germination was promoted by both light and temperature alternation. Seed dormancy was not detected. Temperature dependence of seed germination indicated that H. caspica seeds are able to germinate at any time between spring and autumn in their habitats in China. Seed germination was almost completely withheld when seeds were moistened with 500 mmol kg(-1) NaCl, but seeds remained viable after moistening with 3000 mmol kg(-1) NaCl for 41 d. Opportunities for seed germination were expected to be very limited in the field because for photoblastic H. caspica seeds to germinate, the seeds need to be almost exposed to the soil surface, where they are likely to suffer severe water deficiency and high salinity. It was suggested that germination of H. caspica seeds in the field is facilitated by a supply of a large amount of water from melting snow in early spring.