Kindly sponsored by
The Trees and Shrubs Online Oak Consortium
Article from New Trees by John Grimshaw & Ross Bayton
'Quercus polymorpha' from the website Trees and Shrubs Online (treesandshrubsonline.
There are no active references in this article.
Tree to 20 m or slightly more. Branchlets reddish or greenish brown and tomentose, though soon glabrous with pale lenticels. Leaves sub-evergreen, 5–10(–15) × 3–6(–8) cm, elliptic or ovate, upper surface dark or light green, glossy, glabrous though tomentose when young and with impressed veins, lower surface light green to glaucous with prominent raised veins, largely glabrous, but tomentose and with erect golden hairs when young, 10–12(–14) secondary veins on each side of the midrib, margins entire or with prominent serrations in upper third of leaf, apex rounded, acuminate or retuse; petiole 1.5–2.5 cm long. Infructescence 0.5–1 cm long with one to two cupules. Cupule hemispheric or funnel-shaped, 1.2–2 × 1–1.3 cm; scales acute, grey-pubescent, appressed. Acorn ovoid to ellipsoid, half of its length enclosed in the cupule, yellow-tomentose, 1.4–2.5 cm long with a short stylopodium. Flowering October (USA). Muller 1942, Nixon 1997. Distribution GUATEMALA; MEXICO: Chiapas, Hidalgo, Nuevo León, Oaxaca, Puebla, San Luis Potosí, Tamaulipas, Veracruz; USA: Texas. Habitat Dry, tropical forest, cloud forest, pine-oak woodland, gallery forest, between 400 and 2450 m asl. USDA Hardiness Zone 7. Conservation status Near Threatened. Illustration Nixon 1997.
This widespread but principally Mexican white oak is most frequently represented in collections throughout our area by small young plants only, but in suitable conditions it has the potential to make a fine tree. Seedlings observed at the Cistus Nursery in Portland, Oregon showed considerable variation in the degree of toothing on the leaves. All, however, demonstrated the spectacular red-pubescent new growth that makes this species very desirable. It is not successful in the cool English summers of the Hillier Gardens but is flourishing in Shaun Haddock’s collection in southern France (A. Coombes, pers. comm. 2006). Demonstrating the white oaks’ preference for hot summers, a specimen at the JC Raulston Arboretum is 7 m tall, dbh 12 cm. Planted in 1999, it has formed a single straight trunk with spreading branches, and when observed in June 2006 was just starting the year’s second flush of new growth.