Oaks of the World

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  Quercus barrancana
Author Spellenberg 2014
Synonyms  
Local names  
Range Mexico (SW Chihuahua, NW Sonora, in the Sierra Madre Occidental); 1300-2115 m;
Growth habit shrub or small tree, 1 to 5 m;
Leaves 1.2-3.6 cm X 0.6-1.5; evergreen; dark green; narrowly ovate to oblong; base rounded, sometimes slightly cordate; apex rounded or obtuse, with small mucro at tip; margin usually dentate in apical 2/3 (1 to 4 mucronate, asymmetrical, forward pointing teeth); young leaves with dense, pale, multiradiate hairs on both sides; mature leaves sparsely hairy above or glabrous, lustrous; underneath dull, pubescent or glabrescent, with appressed, crinkled, multiradiate hairs; midvein prominent above; lateral veins 5-9 pairs, not so conspicuous;
Flowers male catkins ca. 2 cm long, greenish yellow, with pubescent axis bearing 10-15 flowers;
Fruits acorn 1.2-1.9 cm long, 0.8-1 cm wide, fusiform, olive brown, enclosed 1/4 to 1/3 by cup; solitary or several together on a 2 cm long peduncle; cup densely short tomentose, yellow brown; maturing the same year, between late June to mid-September.

Bark, twigs and
buds

twig pubescent first year, becoming glabrous third year, reddish brown, slightly fissured; small whitish lenticels; buds almost globose, 1 mm long, slightly pubescent, with scales hairy at margins;
Hardiness zone, habitat previously considered as a variety of Q. toumeyi, which withstands perfectly -18° C; dry, rocky places in Canyons (barrancas) of the Western slope of Sierra Madre Occidental;
Miscellaneous - Section Quercus
- Closely related to Q. toumeyi, from which it differs in having usually dentate foliar margins, and multiradiate, crinkled hairs on the lower leaf side;
Subspecies and
varieties
 
Pictures

Description and pictures of the holotype in the article published by the Author R. Spellenberg: click here