Interior Live Oak
Native to (or naturalized in) Oregon:
- Broadleaf evergreen tree 30-75 ft (923 m) tall, erect, usually single stemmed, short furrowed trunk, ascending or spreading branches, folage may reach the ground; it may also assume a shrub-like form with maximum heights of only 8-10 ft (~2.5-3 m). Leaves alternate, simple, leathery, 2.5-4 cm long, oblong, elliptical or lanceolate, mostly flat, tip acute to pointed, margins entire to spiny toothed, upper surface shiny dark green, lower surface shiny, light or yellow-green. Flowers; male flowers are borne in catkins 2-5 cm in length, whereas female flowers grow in clusters of 2-4 in the upper leaf axils. Fruit (acorn) matures in 2 years, cup about 15 mm wide and similar depth, cup-shaped to hemispheric, encloses about 1/3 of the nut, nut 2-4 cm long, ovoid to cylindrical, tapered to tip, often longitudinally striped.
- Hardy to USDA Zone 7 Native to much of western California, from Siskiyou County in the north, to Baja California; found in interior canyons, slopes, valleys, chaparral, pine and oak woodlands. At least two forms are recognized, Quercus wislizeni var. wislizeni essentially the tree form, Interior Live Oak. Shrub forms with oval leaves 2.5-4 cm long and margins entire or deeply lobed-dentate are treated by some as Quercus wislizenii var. frutescens Bush Interior Live Oak.
- Quercus × morehus (Oracle Oak) is a hybrid between Q. kelloggii (California Black Oak) and Q. wislizeni (Interior Live Oak). The hybrids are known from several populations that occur in southwestern Oregon, northern Douglas County to southern Josephine County, as well as California. The entire to spinose margins of Q. wislizeni are apparent in the leaves of the hybrid, which are quite intermediate between the two parents (H. L. Chambers, The Family Fagaceae in Oregon, Part II: The Oaks). The presence of the Quercus × morehus hybrid in Oregon has led some to suggest that Q. wislizeni was present in southern Oregon at sometime in the past.
- wislizeni: after Frederick Adolf Wislizenus (1810-1889), Army surgeon, explorer, botanist and plant collector of German birth who travelled extensively in the southwestern United States.