Oaks of the World

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  Quercus xylina

Sheidw. 1837 Hort. Belge 4:321. 1837. pl. 18

Diagnosis here

Synonyms laxa Liebm. 1854
callosa Mart. ex A.DC 1864
reticulata var. laxa (Liebm.) Wenz. 1884
Local names
Range Mexico (Durango, Guanajuato, Hidalgo, Jalisco, Queretaro, Sinaloa); 1650-3000 m;
Growth habit 3-10 m tall;
Leaves 6-8 x 3-5 cm; deciduous; coriaceous; thick; oboval or oblong; apex obtuse (sometimes acute), mucronate; base rounded or cordate, sometimes asymmetrical; margin thick, slightly revolute, crenate or with 3-6 mucronate teeth each side on the distal half of the blade; adaxially olive green, slightly rugose, glabrous or covered with scarce stellate and glandular trichomes; abaxially paler, densely and persistently tomentose (fascicled and glandular trichomes); 7-12 vein pairs impressed above, prominent beneath; epidermis white-papillose; petiole 7-13 mm long, tomentose at first, glabrescent;
Flowers flowering in May; male catkins 3 cm, with numerous flowers; female ones 5-10 mm long, with 1-5 pubescent flowers;
Fruits acorn 1.5-2 cm long, ovoid to oblong, glabrous; 1 to 8 together on a 4-10 cm long pubescent peduncle; cup less than 2 cm wide, with appressed scales, covering 1/2 of nut; maturing the same year in September and October

Bark, twigs and

grey, scaly bark; twigs yellowish, 3-4 mm thick, densely tomentose at first, then glabrescent; buds globose, ovoid, rarely conic, 2-3 mm long, with marginally hairy scales; stipules persistent at least one year; lenticels visible only the second year;
Hardiness zone, habitat hardy

-- A. Camus : n° 226 ;
-- Sub-genus Quercus, Section Quercus, Series Leucomexicanae;

-- Closely related to
Q.obtusata, which has subcoriaceous blades, the leaves are wider than in Q. xylina and have scarce fasciculate sessile trichomes on the abaxial surface.
-- Possible confusion with Q. praeco, but this species has an acorn-cup rolled inside and the veins are not impressed adaxially;
-- Resembles as well Q. deserticola which differs in having stellate trichomes abaxially.

Subspecies and