Oaks of the World

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  Quercus microphylla
Author

Née 1801 Anales Ci. Nat. 3: 264

Diagnosis here
Synonyms frutex var. uhdeana Trel. 1924
macrocarpa Endl. 1848, nom. illeg. not Michx. 1801
microphylla var. uhdeana (Trel.) A.Camus 1939
repanda Benth. 1840, not Bonpl. 1809
Local names
Range Mexico in the Trans-Mexican Volcanic Belt (Aguascalientes, Durango, Guanajuato, Hidalgo, Jalisco, Nuevo Leon, Oaxaca, Puebla, Querétaro, Tamaulipas, Tlaxcala, Veracruz, Zacatecas) ; 2000-3000 m ;
Growth habit small shrub 0.4-2 m tall, branched even at base of trunk;
Leaves

1.8-5.5 x 0.7-1.8 cm; deciduous; subcoriaceous; elliptic-lanceolate to oblong-lanceolate; apex attenuated, acute to slightly rounded, often mucronate; base rounded; margins flat to slightly revolute, entire or slightly toothed near apex (1-2 pairs of teeth); lustrous grey-green, rough above, with sessile, 6-15 rays fasciculate hairs and sparce simple not glandular trichomes; yellowish persistent tomentose beneath, woolly, with trichomes like those of the adaxial side, and also with simple glandular uniseriate golden trichomes; 8-10 veins pairs impressed above, prominent beneath; epidermis bullate and papillose, whitish; petiole tomentose 2-6 mm;

Flowers pistillates flowers on a tomentose peduncle reaching 1cm long, 1mm thick;
Fruits

acorn 1-1.5 cm; ovoid, mucronate, stalkless or on a peduncle to 1 cm long; singly or paired; enclosed 1/2 by scaly, half-round cup; cup with straight rim, thin pubescent scales (except their glabrous apex) ; rippening first year, from August to September;

Bark, twigs and
buds

bark fissured into thin, irregular plates, dark grey; twigs 1.5-2.5 mm in cross-section, glabrescent the second year; bud ovoid to globose, 1-2 mm, brown, obtuse, with ciliate scales; lenticels unconspicuous;
Hardiness zone, habitat not hardy; prefers dry, limestone and rocky soils;
Miscellaneous

-- A. Camus : n° 242;
-- Sub-genus Quercus, Section Quercus, Subsection Leucomexicanae, Group Microphyllae;
-- Possible confusion with Q. striatula but this species has more coriaceous, 1-2.5 cm x 0.5-1.4 leaves, margins nearly flat, bulbous glandular trichomes abaxially, an acorn enclosed 1/3-1/4 in cup, and is not taller than 0.5m;
-- This taxon is a member of the Q. microphylla complex (Valencia 2020) composed of Q. cordifolia, Q. deliquescens, Q. frutex, Q. intricata, Q. microphylla, Q. mohriana, Q. repanda and Q. striatula.
Subspecies and
varieties
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