Mexican pinyon is a native, monoecious small tree.
Evergreen needles are in bundles of three or infrequently in bundles of two or four.
Cones require 3 years to mature. Rainfall is positively correlated with the production of the cone buds. Summer moisture stress at the time of cone bud production occasionally may promote an above-average crop of strobili the following spring, indicating that reproductive growth is favored over vegetative growth when trees are stressed. Mexican pinyon and other pinyons produce only a few seeds per cone. Establishment of Mexican pinyon seedlings depends on the availability of adequate water during the first dry seasons.