[Wikipedia] Habitat & Precipitation Needs: Monolopia major has very high to strict edaphic affinity for clay soils, particularly vertic clay (smectite; montmorillonite) soils. M. lanceolata typically may grow on all soil textures from sandy to clayey, but M. major only grows on clayey soils. M. major appears to only occur where average annual precipitation is greater than about 11 inches per year (chaparral, blue oak woodland), whereas M. lanceolata can occur at average annual precipitation greater than 11 inches per year, but also at precipitation levels as low as 6 inches per year (San Joaquin Valley Desert; saltbrush scrub). Most known large populations of M. major are distributed around San Benito Mountain in southern San Benito County. (link added by Mary Ann Machi)