Quercus sillae Trel. 1924

Twigs slender (1-2 mm.), fluted, glabrous. Leaves deciduous, oblong, entire
to undulately few-toothed, subacute, rather blunt at base, glabrous and glossy
above, minutely but densely ashen-tomentulose beneath, small (about 1.5 x 4 cm.);
veins about 12 pairs, rather obscurely looping; petiole glabrous, some 2 mm. long.
Catkins?. Fruit (young) annual, sessile, solitary or paired; cup with thin acute
appressed rather coarse gray scales.
Eastern Sierra Madre region of Mexico.