Oaks of the World

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  Quercus hypoxantha
Author Trel. 1924
Synonyms errans fo. graciliformis C.H.Muller 1936
Local names  
Range Mexico (Coahuila, Nuevo Leon, San Luis Potosi, Tamaulipas); 2100-2950 m;
Growth habit usually less than 3 m tall;
Leaves

3-5 cm long, 1.5-3.5 wide; semi-evergreen; leathery; oboval or oblong-oboval; often folded lengthwise; apex variable, most often obtuse, aristate; base varying : usually cordate; margin thick, revolute, wavy, with 3-4(-6) sharp, bristle-tipped teeth; light green or grey green (sometimes darker) above, with minute, scattered hairs of various types except glandular; abaxially with dense, woolly, yellow tomentum (made of fascicled hairs and golden uniseriate glandular ones, both of them evenly and equally laid out), persistent but easily scratchable, sometimes desappearing with age, covering all the limb including the 6-8 vein pairs; midrib and lateral veins impressed above; epidermis usually bullate and papillose; petiole 0.5 cm long, reddish, glabrescent; 

Flowers in June; male inflorescence 5-6 cm long, with more than 20 flowers; pistillate inflorescence less than 1 cm long, with 1 or 2 flowers, stalkless or on tomentose peduncle 1-4 mm long;
Fruits acorn ovoid, 1-1.5 cm long; solitary or 2-3 together, sessile or on a 2-5 mm long peduncle; cup half-round with rounded, flat, tomentose scales; cup enclosing 1/2 of nut; maturing in 2 years in September; cotyledons free;

Bark, twigs and
buds

bark smooth, dark grey; twig slender, thin (to 2 mm in diameter), persistently yellowish pubescent; very small bud (2-3 mm long), ovoid, glabrous, with ciliate scales; stipules 2 mm long, seldom persistent;
Hardiness zone, habitat probably hardy zone 7;
Miscellaneous -- A. Camus : n° 367;
-- Section Lobatae;
-- Related to Q.hintoniorum (which differs in having the abaxially not glandular trichomes only at the vein axils, and cupules covering only 1/4 or 1/3 of the nut); it forms the "Quercus hypoxantha complex Nixon & Muller 1993", in association with mainly Q. hintoniorum, Q.coahuilensis and Q.miquihuanensis, and less often with Q. galeanensis, Q. saltillensis and Q. jonesii.
Subspecies and
varieties
 
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