Oaks of the World

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  Quercus laeta
Author

Liebm. 1854 Overs. Kongel. Danske Vidensk. Selsk. Forh. Medlemmers Arbeider 1854: 179

Diagnosis here
Synonyms centralis Trel. 1924 Diagnosis here
clivicola Trel. & C.H.Muller 1936     (A. Camus : 206)
laeta f. heterophylla Trel. 1924
obscura Trel. 1924, nom. illeg., not Seem. 1897
pallescens Trel. 1924 Diagnosis here
pandurata var. laeta (Liebm.) Wenz. 1884
prinopsis Trel.1924    (A. Camus : 230) Diagnosis here
transmontana Trel. 1924 (A. Camus = n° 252) Diagnosis here
Local names encino algodoncillo; encino colorado;
Range Mexico (Aguascalientes, Coahuila, DF, Durango, Guanajuato, Hidalgo, Jalisco, Mexico, Michoacan, Nayarit, Nuevo Leon, Sinaloa, San Luis Potosi, Zacatecas); 2300 - 2700 m;
Growth habit 5 - 10 m tall; sometimes shrub to 60 cm high; crown broad; branches twisted, spreading;
Leaves 5-15 x 2-5 cm; deciduous; thick, leathery, stiff; oblanceolate, oblong-lanceolate or oboval, seldom elliptic; apex round or acute, mucronate; base cordate or subcordate, sometimes asymmetrical; margin thick, slightly revolute, undulate, entire or crenate, or most often with 3-6 pairs of mucronate teeth on the apical 2/3; lustrous olive green above, rough, nearly glabrous or with 9 rayed sellate trichomes on the whole surface and simple uniseriate glandular trichomes along midrib, especially the base; pale glaucous beneath, glabrescent, with an even indumentum made of long, shortly pediculate, 9-rayed spreading stellate hairs, without masses of glandular secretions but with few glandular trichomes, mostly on veins; 6-11 vein pairs impressed above, prominent beneath, ending in the mucro of the teeth, the basal veins forked and anastomosed before reaching the margin; epidermis white-papillose ; petiole pubescent 2-10 mm long;
Flowers flowering in May; male catkins 4-6 cm long, with numerous flowers; female ones 1-3 cm long, with 1 to 3 pubescent flowers;
Fruits acorn ovoid, 0.6-1.3 cm long, 0.6-0.7 cm in diameter; singly or to 3 sessile or on a short peduncle less than 5 cm long; apex obtuse, mucronate; enclosed 1/3 or 1/2 by cup; cup 0.8-1.1 cm in diameter, with pubescent scales narrowed at apex and thickened at base; maturing in 1 year, from September to November;

Bark, twigs and
buds

dark greyish bark; twigs 1.5-3.5 mm thick, tawny, floccose-glabrescent (fascidulate trichomes and long simple ones), grooved, with few pale yellow lenticels; bud globose or ovoid, obtuse, 2-4 mm long, 1.5-2.5 wide; stipules hairy, deciduous, 4-6 mm long;
Hardiness zone, habitat hardy; prefers dry, rocky soils;
Miscellaneous

-- A. Camus : n° 232 ;
-- Sub-genus Quercus, Section Quercus, Subsection Leucomexicanae, Series Glaucoideae;

-- Q. laeta shows extensive morphological variation throughout its distribution, which makes it a problematic species. However, it can be distinguished by its abaxial blade surface which is covered with long stellate shortly stipitate trichomes, lacks amber glandular trichomes, and usually has appressed acute unicellular trichomes along the midvein ; the abaxial epidermis is white-papillose and appears glaucous.

-- Related to Q.obtusata with which it hybridizes frequently; Q. laeta differs from Q. obtusata which has larger leaves, the foliar underside pale green with abundant glandular hairs and glandular secretions, and a foliar margin never entire.
Subspecies and
varieties
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