Because Asclepias fascicularis is found on both serpentine and non-serpentine soils in California and because it was reported to accumulate sodium, this study was initiated to establish the degree of accumulation of this ion in these two soil types. Two other species, Asclepias speciosa Torr. and Asclepias cordifolia (Benth.) Jeps. were included to determine if this characteristic of accumulation occurs in other members of this genus.

Do the peculiar ion concentrations of serpentine soils appear in the tissues of plants growing on those soils? To what extent are the same species of plants growing in serpentine and non-serpentine soil similar in ionic concentrations? This work was an attempt to answer these questions.