Oaks of the World

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 Quercus urbanii
AuthorTrel. 1924
Synonyms pennivenia Trel. 1924
conzattii Trel. 1921
Local names encino cucharillo;
Range Mexico (Guerrero, Durango, Jalisco, Nayarit, Mexico, Sonora, Zacatecas); 1500 - 2500 m ;
Growth habit6-12 m tall, with trunk to 0.3 m in diameter or more; thick branches very tomentose;
Leaves 14-30 cm; deciduous; almost orbicular, or panduriform; stiff; convex; reticulate epidermis adaxially ; apex rounded; base narrowly cordate; margin thick, revolute, cartilaginous, entire or wavy-dentate with 5-20 pairs of small aristate teeth at apical 2/3; adaxially pale green, lustrous, rough, glabrous except simple glandular hairs and stellate ones on veins; densely yellowish tomentose beneath with stalked stellate trichomes on the whole surface of the blade; 9-11 vein pairs, sinuous or curved, seldom straight; epidermis papillose and glandular; petiole 2-4 cm long, tomentose; young leaves conspicuously red and hairy;
Flowers in December-January; male catkins 10-20 cm long, with pubescent axis and numerous flowers; pistillate flowers on 4-15 cm long tomentose racemes;
Fruits acorn 8-10 mm long, ovoid; 6 to 10 together on a yellow tomentose stalk reaching 9 cm long; small cup, half-round, enclosing 1/3 or 1/2 of nut; maturing in 1 year, in October;

Bark, twigs and
buds

twigs 6-10 mm thick, yellow grey tomentose during several years, with inconspicuous lenticels; buds 5-10 mm long, ovoid, brown; stipules persistent around terminal buds, 7 mm long;
Hardiness zone, habitatnot hardy; poor calcareous soils;
Miscellaneous -- A. Camus : n° 311;
-- Section Lobatae; subsection Racemiflorae;
Subspecies and
varieties
Q. conzattii Trel. 1921
= Q. urbanii f. parvifolia Martinez 1954
Many Authors consider it as a true species. However it is different from Q. urbanii only in having all its parts smaller and leaves never panduriform.
Tree to 3-15 m; twigs thick (4 mm), with dense, yellowish persistent pubescence; leaves obovate or suborbicular, convex, 6-14 cm long x 4-12 wide; apex variable, base obtuse and cordate; margin revolute, with 10 pairs of bristle-tipped veins; adaxially pale green, glabrous except on veins; abaxially with yellowish pubescence; 9-11 pairs of straight secondary veins impressed adaxially; petiole 1-2 cm, densely pubescent; male catkins with 30 flowers, female ones with 2-8 flowers; flowers in March; acorn 1 cm long, to 5 or more on a 1-1.5 cm long peduncle, maturing first year in August, cup enclosing 1/3 or 1/2 of nut; Mexico (Durango, Jalisco, Nayarit, Oaxaca, Zacatecas); 1700-2800 m;
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