NTS in Area 11. The floristic composition for these sites generally is more complex than it is for most of the other study sites, partly because Area 11 is located within the transition zone between the Great Basin and Mojave Deserts. The vegetation of Area 5 (GMX) is typically Mojave Desert, whereas that in Area 13 is more representative of the Great Basin Desert flora. The vegetation of study sites located on the Tonopah Test Range is common to the Great Basin Desert. The data presented in Table 2 have been taken from the corrected stratum areas given in an earlier progress report (Gilbert et al., 1975a). These areas are presented here so that the reader can relate the inventory estimates more easily to the land area represented by the activity strata of each fallout area. Table 3 gives the estimated inventory of 2399240py for vegetation in the aged fallout areas under investigation. It should be understood that these vegeta- tion inventories are only approximate, since the average biomass data used in the calculations were approximated using dimensional analyses (linear regression of biomass on shrub volume) based upon small numbers (see Table 1) of 2 x 50 meter sampling quadrants randomly selected within large areas. Furthermore, all plant species have been lumped together to get an average radionuclide concentration; again the formula for S.E. for inventory is only approximate, being based upon a Taylor series expansion. Neverthless, these results should give a general impression of the relative magnitude of vegetation contamination within each of these aged fallout areas. The standing biomass of vegetation varied from about 200 to 600 g/m? (2,000 to 6,000 kg/hectare). Estimates of new leaf and stem production for vegetation of the kind found in these study areas normally are much less than 10 percent of the standing biomass (Kaaz, 1972; Turner and McBrayer, 1974). These estimates represent very low levels of new primary productivity when compared to good grassland or cultivated forage production. However, it should be under- stood that the standing biomass of these fallout areas is mainly in the form of woody shrubs containing stem material which can be many years old, depending upon the species involved. Data reported previously (Romney et ai., 1974, 1975) indicate that most of the contaminant found on this kind of vegetation is attributable to resuspended material deposited upon the external surface of foliage. The estimated vegetation-to-soil inventory ratios given in Table 3, last column, indicate that a greater proportion of the deposited source material can move onto the vegetation at locations farther away from ground zero. is thought to reflect an initial partitioning in the particle size of the This fallout material originally deposited within the fallout pattern. The mean particle size of the fallout material generally decreased at greater distances downwind from ground zero (Romney et al., 1963). Inasmuch as the resuspendable source material entrapped upon plant foliage represents only a limited particle size range, that which is deposited upon foliage contributed less activity in proportion to the total amount of fallout contamination deposited on soil at points nearer to ground zero compared to points farther away. The estimates of 239°240py inventory (in millicuries) for vegetation in the fallout areas located on NTS were 0.47 + .073 (S.E.) for Area 5 (GMX); 0.098 + -045, 2.2 + .028, 3.8 + .70, and 6.7 +t 38 .73 for Area 11, Sites A, B, C, and D,