Among laymen and agriculturists it is a common expression that certain spots in a field are acid. The term "acid spots" has come to be used more and more since soil reaction has been shown to have some bearing upon the soil preferences of many plants. That there is a correlation between the hydrogen-ion concentration of the soil and natural plant distribution has also been shown by a number of writers (6, 9, 14, l5). Rumex acetosella has been considered to be an acid indicator (1, 5). The purpose of this paper is to determine if there is a consistent correlation between the hydrogen-ion concentration of the soil and the distribution of a native species.