Oaks are wildlife keystone species hosting a mind-boggling number of insects. This brings in a vast array of substrate-insectivorous birds (birds that spend their time on these trees eating the insects). The acorns are important food for many birds and mammals (and some species eaten by people). The trees also provide important habitat for many birds and mammals. Almost all the oaks host a multitude of moths and butterflies including the Arizona sister (Adelpha eulalia), the dull firetip (Apyrrothrix araxes), the Short-tailed Skipper (Zestusa dorus), the sleepy duskywing (Erynnis brizo), the Meridian Duskywing (Erynnis meridianus), the Juvenal’s duskywing (Erynnis juvenalis), the llavia Hairstreak (Satyrium ilavia), the Gray Hairstreak (Strymon melinus), the Colorado Hairstreak (Hypaurotis crysalus), the Golden Hairstreak (Habrodais grunus), and more.

Oak acorns are edible but most species are high in tannins and need much processing—they are leached with many exchanges of water.

Quercus is the classical Latin word for oak, thought to be derived from Celtic quer, fine, and cuez, tree, while toumeyi is named for James W. Toumey (1865-1932) a botanist and professor at the University of Arizona.

Found on rocky slopes in chaparral and oak forests from 4,000-6,500 ft. in southern Arizona, southwestern New Mexico, southern Texas; south into northern Mexico.