Quercus × undulata Torr.

Utah, Arizona, New Mexico, Texas; Mexico (Chihuahua);

1 to 3 m; rarely reaches 8 m;

evergreen; 4-9cm long, 3-5 wide, lustrous and light glaucous above, light brown tomentose beneath; margin with 2-5 pairs of pointed and mucronate lobes;

acorn 1.5-1.8cm long, mucronate, light brown, enclosed for 1/3 of length in bowl-shaped, reddish brown cup; maturing in 1 year;

hardy; all types of soils.

– A. Camus = n° 261; – Sub-genus Quercus, Section Quercus; sub-section Undulatae; – The species Q.gambelii hybridizes frequently, creating a population of hybrids described under the name “ Q. x undulata complex “ by Little in 1979, in order to change the name Q.undulata Torr.1827 ; the previous term was the name of a species whose common name is “wavyleaf oak”, or “Rocky Mountain shin oak” ; J.M. Tucker, in 1971, had yet indentified the main parents of this hybrid species : Q. turbinella , Q  grisea , Q. havardii , Q.mohriana , Q arizonica and Q.muehlenbergii ; hybrids between Q  gambelii and an evergreen species are often semi-evergreen; – The name “undulata” inspired many Authors ! One can list the following : Q.undulata Engelm 1878 (= Q.sinuata Walt.), Q.undulata Kit.1863 (= Q.pubescens Willd.), Q.undulata Benth. 1841 (= Q.benthamii A.DC), Q.undulata K.Koch 1847 (= Q.lusitanica Lam.), Q.undulata Torr 1827 (= Q.x undulata complex Little 1979), Q.undulata Sarg., and A.DC (more or less = Q.x pauciloba …), Q.undulata S. Wats. (= Q.gambelii Nutt.); – OOTW reports hybrid: Q. × andrewsii (Q. macrocarpa × Q. × undulata)