-29- different rates. In Scaevola the rate of decline of the basal and terminal leaves was rapid post Nectar, (t72-2) for about 50 days then when the pre-Nectar level was reached, was much slower (t 70-4) sor the remainder of the study. it The decline of radioactivity of the terminal leaves is shown in Figure 9. In the flowers, scorched leaves, the entire period the rate adventitious shoot leaves, of decline was rapid (for flowers see Figure 10). and (t 72-0) for The differ- ences in the rates of decline of radioactivity of these tis- sues may be due to the fact that the terminal leaves were protected by older leaves and were not exposed to fallout to the game degree as the flowers and scorched leaves. This difference in rate of decline may reflect the uptake of longerlived fission products by the protected leaves. In the stems the rate of decline was less rapid than in other tissues. Figure 11 shows the decline of radioactivity of the entire stem. In each of these figures the decay of mixed fission products according to Hunter and Ballou ‘15) ig included for comparison. In Messerschmidia therewere also three types of decline, these tissues having the same type of radioactive decline as the Scaevola tissues ever, the decline was in Portulaca, (Figs.9-11). the same In the other species, for each tissue: Triumfetta and Boerhaavia, how- for example, the rate of declire fr