Oaks of the World

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 Quercus obtusata
Author Humb. & Bonpl. 1809 Pl. Aequinoct. 2: 26
Synonyms alvarezensis Trel. Diagnosis here
atriglans Warb.1939
crenatifolia Trel. 1924 Diagnosis here
hartwegii Benth. 1840 (Camus = n° 225)
hartwegii f. glabrata Trel. 1924
innuncupata Trel. 1924 Diagnosis here
obtusata var. hartwegii A.DC 1864
pandurata var. hartwegii Wenz. 1884
pandurata Humb. & Bonpl. 1809
panduriformis Trel. 1924 (A. Camus = n° 234) Diagnosis here
rugosa sensu Trel., not Née
spicata Bonpl. 1809 not Sm 1916
Local namesencino calicahuac; encino cosahuicahuatl; uricua; charari; tocuz;
Range Mexico (Aguascalientes, Guerrero, Durango, Guanajuato, Hidalgo, Jalisco, Mexico, Michoacan, Morales, Nayarit, Oaxaca, Puebla, Queretaro, San Luis Potosi, Tlaxcala, Veracruz, Zacatecas); 620-2800 m;
Growth habit 7-12 (15) m tall; trunk to 20-40 cm in diameter;
Leaves 7-14 x 4-8 cm ; deciduous ; more or less broadly oboval, or oblong, seldom elliptic; thick, subcoriaceous or coriaceous; flat, sometimes slightly convex; apex rounded or obtuse, mucronate; base rounded to cordate, or truncate; margin thick, crenate rather than dentate (if so, 3-8 pairs of teeth in the distal half ending in a short, stout mucro, bending toward the abaxial side), seldom entire; olive green, lustrous above, with fascicled, stellate and simple glandular hairs mainly at base of midrib, glabrescent; beneath pale green, dull, tomentose mostly on veins (tomentum made of 5-8 rays fascicled, sessile or not, trichomes, and numerous amber or reddish glandular hairs, and abundant glandular secretions); 9-12 vein pairs slightly impressed above; epidermis whitish-papillose, remotely bullate; petiole glabrescent 5-11 mm;
Flowers in April-May; staminate inflorescences 3-10 cm long, with numerous flowers; pistillate flowers pubescent, 3 to 15 or more, near the tip of a pubescent, 14 cm long peduncle;
Fruits acorn 1-1.6 cm long, globose, sometimes ovoid; apex rounded, mucronate; single or 2 to 5 together ; peduncle slender, hairy, 2-3 cm long; enclosed 1/2 by cup; cup half-round 1.5-2 cm in diameter, with loose, appressed, grey tomentose scales; maturing in 1 year from September to November; edible;

Bark, twigs and
buds

bark fissured into plates; twigs slender (1-3 mm thick), grey or black with stellate and glandular trichomes, glabrescent; numerous pale lenticels; buds ovoid, grey brown, 2-4 mm, scales ciliate at margin; stipules linear, 3-9 mm long, pubescent, deciduous;
Hardiness zone, habitat zone 8;
Miscellaneous -- A. Camus : n° 233 ;
-- Sub-genus Quercus, Section Quercus, Series Leucomexicanae;
-- Q. alvarezensis is, for Govaerts (2007) synonym of Q. rugosa Née...
-- Q.spicata Sm 1919 is actually Lithocarpus spicatus (Sm) Rehd. 1919
-- Resembles Q. potosina which has smaller leaves (3-10 x 2-6 cm); resembles too Q. rugosa, this one has a convex leaf strongly coriaceous, a revolute margin, the epidermis bullate; at least, one can differenciate Q. obtusata from Q. laeta which has foliar underside pale glaucous, without masses of glandular secretions, none or rare glandular trichomes, a leaf more oblong than oboval with a margin sometimes entire.
Subspecies and
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