Quercus radiata Trel.

Mexico (Durango, Jalisco, Zacatecas); 2000-2600 m;

6-12 m; trunk to 0.5 m in diameter;

8-10 x 7-10 cm; oboval to suborbicular; coriaceous; apex obtuse aristate or shortly acuminate; base cordate to auricled; margin flat or slightly revolute, with 4-8 pairs of aristate, short teeth in apical 1/2; adaxially olive green, epidermis reticulate, with trichomes multiradiate (8-10 rays 0.1-0.2 mm long), fascicled ones, stipitate or not, and golden uniseriate glandular ones; abaxially densely tomentose made of fascicled hairs and glandular ones, tomentum which does not hide totally the papillose, reticulate epidermis, becoming somewhat glabrate with dark globules of coalesced glandular excrescence; 8-10 vein pairs, impressed above, prominent beneath; petiole pubescent, brown, 1 cm long;

acorn 6-11 mm, globose, to 8 or more together on the raceme, on a 4-12 cm long infrutescence; cup hemispherical, margin straight, 6-8 mm in diameter, with pubescent scales; cup enclosing 1/3 or 1/2 of the nut; maturation first year;

– Sub-genus Quercus, section Lobatae, Series Erythromexicanae, Group Racemiflorae; – Threatened (IUCN Red List Category : EN). – Resembles Q. jonesii , but this species has only 1-3 acorns together, stalkless or on a peduncle less than 5 mm long, with fascicled stipitate hairs only at axils, and a smooth surface adaxially; moreover, for some Authors (L. Vazquez & K.C. Nixon 2013) Q. radiata could have a hybrid origin between Q. urbanii (or Q. conzatii ) and Q. jonesii.