Caption
Two forms of A. costata sensu lato from Montana. The elliptic form with evenly spaced areolae in figs 1-5 was collected from Brush Lake, Sheridan County (MDC 074601). The typical rhombic-lanceolate form in figs 6-11 was collected from Alkali Lake, Lincoln County (MDC 123101) and White Lake, Sheridan County (MDC 141901).
