The prehistoric ecology and plant community of the Waterman Mountains area of Arizona has been reconstructed to its composition as far back as the last glacial period, the Late Wisconsin glacial period. Dominant trees of that era, based upon pollen records, were Utah juniper (Juniperus osteosperma), single-leaf pinyon (Pinus monophylla), and redberry juniper (Juniperus pinchotii), along with canotia (Canotia holacantha), and understory plants including Monardella arizonica.