Quercus grisea Liebm.

Southwest Texas; North and Center of Mexico; 1500-2700 m;

4-7 m, sometimes to 10 m, but smaller in cultivation; trunk short, 10-30 cm wide;

3-7 x 1-3 cm; semi-evergreen; thick, stiff, subcoriaceous; oblong, elliptic, obovate, rarely ovate; 2-3 times longer than wide; apex pointed or obtuse, mucronate; base rounded to cordate; margin flat, entire, or often when youth crenate-dentate, with 1-4 pairs of mucronate teeth near apex; glaucous grey, slightly lustrous above with stalkless, stellate hairs; greyish green , hairy velutinous beneath, with dense, stalkless, appressed stellate, two sizes trichomes; 6-12 vein pairs, remotely raised above or sometimes flat, prominent beneath; epidermis slightly bullate, waxy; petiole pubescent, 2-8 mm long;

in April; male catkins 4-7 cm long, with more than 20 pubescent flowers; female inflorescences 1-4 cm, with 1 to 8 flowers slightly tomentose;

acorn 1.2-2 cm long; singly or paired or more; short peduncle 0-3 cm long; cup half-round, greyish tomentose, enclosing 1/2 of nut; cup scales with base thickened; maturing in 1 year from September to October; cotyledons connate;

– A. Camus : n° 179; – Sub-genus Quercus, Section Quercus, Series Leucomexicanae; – Possible confusion with Q. chihuahuensis but this species has abaxial foliar trichomes fascicled stipitate; – Q. grisea can as well be confused with Q. microphylla and Q. frutex ; however Q. grisea can be distinguished from both species by its tree habit, and densely velutinous leaves with appressed stellate trichomes which completely cover both surfaces. Q. microphylla and Q. frutex are shrubs and have leaves with fasciculate trichomes on the abaxial blade surface. Additionally Q. frutex has leaves with revolute margins while those of Q. grisea have flat margins.