Quercus barrancana Spellenberg

Mexico (SW Chihuahua, NW Sonora, in the Sierra Madre Occidental); 1300-2115 m;

shrub or small tree, 1 to 5 m;

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;

male catkins ca. 2 cm long, greenish yellow, with pubescent axis bearing 10-15 flowers;

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.

• Sub-genus Quercus, Section Quercus, Series Leucomexicanae; - Closely related to Q. toumeyi , from which it differs in having usually dentate foliar margins, and multiradiate, crinkled hairs on the lower leaf side;