When the intact seeds of forty-two species were exposed to a salt-isotope solution containing 22Na it was found that about 75% of the different seeds showed signs of accumulation of the 22Na. All halophytes and species associated with halophytes, with one exception, displayed the above-mentioned pattern. The seeds responded to a 24 hour exposure period by either decreasing, remaining essentially the same, or increasing in uptake of 22Na as compared with an 8 hour exposure period. Surface area of the seeds, as determined for twenty species, had no apparent relationship to 22Na uptake. The time interval to first germination showed a relationship to sodium uptake for grasses only, and this was valid only up to a 48 hour germination period. The two grasses Oryzopsis hymenoides and Secale montanum. were for some reason an exception to the above trend. The per cent total germination of the seeds after 149.5 hours showed no relationship to 22Na uptake.