Clover's next expedition was on the San Juan River and in Texas, where she gathered fossil plant specimens, which was followed by a 1939 trip to Havasupai Canyon in Arizona. She published the findings from these trips in a 1941 article co-authored with Jotter entitled "Cacti of the Colorado River and Tributaries". In the years afterward, Clover focused her research on the deserts of Mexico and Guatemala and also did some work in Haiti.[2]