Oaks of the World

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  Quercus mexicana
Author Bonpl. 1809 Pl. Aequinoct. 2: 35
Synonyms castanea var. mexicana (Bonpl.)A.DC 1864
castanea var. integra Oerst. 1871
mexicana f. lanulosa Trel. and f. perfertilis Trel.
mexicana fo. bonplandii Trel. 1924
malifolia Trel. 1924 Diagnosis here
pablillensis C.H.Muller 1942
rugulosa Mart. & Gal. 1843 (A.Camus n° 380)
rugulosa f. subtruncata Trel. 1924
sipuraca Trel. 1924
Local names encino tezahuatl;
Range Mexico (Coahuila, Guanajuato, Hidalgo, Mexico, Nuevo Leon, Puebla, Querétaro, San Luis Potosi, Tamaulipas, Tlaxcala , Vera-Cruz); 1600-3050 m;
Growth habit usually small tree to 3-8 m high, but reaches 20 m;
Leaves

810 x 1-3 cm; deciduous; oblong, elliptic or oblong-oboval; apex obtuse or rounded, shortly bristle-tipped; base round to cordate, seldom truncate; margin thick, slightly revolute, cartilaginous, often undulate, entire; adaxially dark green, lustrous, hairless except some stellate hairs along midrib and at the base; beneath with pale grey brown tomentum made of scattered, tangled, fascicled trichomes, like dots on the epidermis, and axil tufts; 7-12 vein pairs nearly flat adaxially, slightly prominent beneath (even though midrib is strongly raised), straight but forked and anastomosed before reaching margin, at an angle of 45-50° with the midrib; adaxially the midrib is sunken; epidermis smooth, or papillose, not bullate; petiole 2-8 mm long, hairy at first, then glabrescent, with the base pinkish;

Flowers male catkins 3-5 cm long, woolly; female inflorescences less than 0.5 cm long, with 1-4 pubescent flowers;
Fruits acorn 0.8-1.4 cm long, subglobose, hairless except at mucronate apex; singly or to 2-3 together, on a peduncle less than 0.5 cm long; cup halfround with rim not rolled inside, enclosing 1/3 to 1/2 of nut, with apicaly rounded pubescent scales; maturing in 2 years between August and January;

Bark, twigs and
buds

bark scaly, light grey; twig slender (1.5-2 mm thick), angled in cross-section, brown stellate tomentose at first, becoming hairless, grey brown; lenticels of the same colour, reaching 11 mm long; bud 2-3 cm long, ovoid, slightly pointed, with ciliate scales ; stipules 3-5 cm long, deciduous or sometimes persistent around apical bud;
Hardiness zone, habitat hardy in zone 7 (withstands -15° C); perfers dry soils; fast growing;
Miscellaneous -- A.Camus : n° 313;
-- Sub-genus Quercus, section Lobatae; sub-section Mexicanae;
-- One must not confuse this taxon with Q. mexicana Benth. 1840 not Bonpl.1809, which is a synonym of Q. crassipes Bonpl. 1809;
-- Possible confusion with Q. eduardi as both have contorted fascicled hairs abaxially ; however eduardi has leaves oblong or oblanceolate or elliptic-oboval, with margin usually toothed near apex, and 5-8 vein pairs.
-- Different from Q. crassipes, in having less vein pairs (to 19 for crassipes), abaxially with contorted trichomes looking like dots (even indumentum for crassipes), cupule with erect margin (involute for crassipes), secondary veins at an angle of less than 90° (near to 90° for crassipes) and a petiole likely pubescent (glabrescent for crassipes)
Subspecies and
varieties
-- Hybridizes with Q. grahamii.
Pictures