Oaks of the World

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  Quercus delgadoana
Author S. Valencia- Avalos, K.C.Nixon & L.M.Kelly 2011 Novon 21: 275
Local names
Range Mexico, in the Sierra Madre Oriental (Hidalgo, Puebla, Veracruz); 1400-2200 m;
Growth habit 25 m tall; trunc to 1 m in diameter;
Leaves 7-18 x 1.5-5 cm, narrowly oblong, elliptic or lanceolate; leathery; both sides glaucous, but paler beneath; apex pointed or acuminate, aristate; base rounded ou cuneate; margin entire, slightly thickened, revolute; adaxially hairless, dull, grey-green somewhat glaucous, without stellate or glandular trichomes; abaxially glabrous or with sometimes some fasciate hairs at axils; (9-)14-20 vein pairs, slightly impressed or nearly flat above and slightly raised beneath, parallel, nearly straight, branched and anastomosed near margin; slightly papillar epidermis; petiole thin, 2-6 mm long, darkened near base;
Flowers pistillate inflorescence at leaves axils, with flowers solitary or paired on a 1.8-2 mm long peduncle;
Fruits acorn ovoid, 2 cm long, 1,2 cm wide, glabrous outside; solitary or paired, short hairless peduncle; cup conical or slightly turbinate, 0.6-1.5 cm in diameter, with margin not rolled, ovate scales that are greyish near base, more or less glabrous; maturing in 2 years, in October-November;

Bark, twigs and

twigs 2-3 mm thick, hairless, with inconspicuous lenticels; buds conical, hairless, 1-2.5 mm long, with more or less elongate scales ciliate at margin; deciduous stipules;
Hardiness zone, habitat hardy zone 7; wet montane forests;

-- Sub-genus Quercus, section Lobatae, Series Erythromexicanae;
-- Very rare species. Threatened (IUCN Red List Category : EN)

-- Differs from Q. sapotifolia which has acorns maturing first year, and leaves that are not slightly glaucous ; it differs also from Q. laurina and from Q. affinis which have a flat blade margin and fewer secondary veins (6-10 and 5-9);


Subspecies and