Oaks of the World

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  Quercus laxa

Liebm. 1854 Overs. Kongel. Danske Vidensk. Selsk. Forh. Medlemmers Arbeider 1854: 181

Diagnosis here

Synonyms xylina Sheidw. 1837 Hort. Belge 4:321. 1837. pl. 18
callosa Mart. ex A.DC 1864
reticulata var. laxa (Liebm.) Wenz. 1884
Local names  
Range Mexico (Durango, Guanajuato, Hidalgo, Jalisco, Queretaro, Sinaloa); 1650-3000 m;
Growth habit 3-10 m tall;
Leaves 6-8 x 3-5 cm; deciduous; coriaceous; thick; oboval or oblong; apex obtuse (sometimes acute), mucronate; base rounded or cordate, sometimes asymmetrical; margin thick, slightly revolute, crenate or with 3-6 mucronate teeth each side on the distal half of the blade; adaxially olive green, slightly rugose, glabrous or covered with scarce stellate and glandular trichomes; abaxially paler, densely and persistently tomentose (fascicled and glandular trichomes); 7-12 vein pairs impressed above, prominent beneath; epidermis white-papillose; petiole 7-13 mm long, tomentose at first, glabrescent;
Flowers flowering in May; male catkins 3 cm, with numerous flowers; female ones 5-10 mm long, with 1-5 pubescent flowers;
Fruits acorn 1.5-2 cm long, ovoid to oblong, glabrous; 1 to 8 together on a 4-10 cm long pubescent peduncle; cup less than 2 cm wide, with appressed scales, covering 1/2 of nut; maturing the same year in September and October

Bark, twigs and

grey, scaly bark; twigs yellowish, 3-4 mm thick, densely tomentose at first, then glabrescent; buds globose, ovoid, rarely conic, 2-3 mm long, with marginally hairy scales; stipules persistent at least one year; lenticels visible only the second year;
Hardiness zone, habitat hardy

-- A. Camus : n° 226 ;
-- Sub-genus Quercus, Section Quercus, Series Leucomexicanae;
-- Closely related to
Q.obtusata, which has subcoriaceous blades, the leaves are wider than in Q. laxa and have scarce fasciculate sessile trichomes on the abaxial surface. Possible confusion with Q. praeco, but this species has an acorn-cup rolled inside and the veins are not impressed adaxially; resembles as well Q. deserticola which differs in having stellate trichomes abaxially.
-- For Susana Valencia 2017, Q. xylina is a synonym of Q. laxa, and moreover it is the correct name for this taxon, as it has priority above Q. laxa..

Subspecies and