Additional index words. Germination, temperature.

Seeds of four citrus cultivars commonly-used for root- stocks, 'Pineapple' sweet orange (Citrus sinensis L. Osbeck), sour orange (C. aurantium L), trifoliate orange (Poncirus trifo- liata L Raf.), and rough lemon (C. jambhiri Lush) were germi nated at temperatures ranging from 4.4∞ to 37.8C using a temperature gradient bar. Seedcoat removal reduced the time necessary for germination, increased the range of tempera tures at which germination occurred, but did not affect the op timum temperature for germination. The optimum temperatures for germination agreed with previous research but the minimum temperatures did not. Rough lemon germi nated at lower temperatures than sweet orange and sour or ange. Trifoliate orange seed germination occurred at the lowest temperatures.