Quercus convallata Trel.

Mexico (Durango, Jaliso, Nayarit) ; 2300-2500 m;

small shrub less than 3 m tall, to tree 10-15 m;

5-12 cm long x 3-6 wide, deciduous; leathery; obovate or oblong to elliptic-obovate; less than twice as long as wide ; apex obtuse, mucronate; base obtuse to cordate, sometimes oblique; margin thick, plane, sinuate or with 3-8 inconspicuous mucronate teeth; light green or olive green beneath, slightly lustrous, with persistent pubescence made of scattered fasciculate trichomes, especially at the base near the midrib, without glandular hairs; abaxially paler, with fasciculate trichomes and rare yellowish or whitish glandular ones; 9-12 veins pairs, straight or slightly curved; epidermis bullate and papillose; petiole 5-15 mm, persistently pubescent;

male catkins 4-6 cm long, with numerous flowers;

acorn 10-18 mm long, often sessile, or on a peduncle seldom more than 1 cm long; solitary or to 3; cup half-round with straight rim and pubescent scales, enclosing 1/3 of nut; maturing first year in July;

– A. Camus : n° 185; – Sub-genus Quercus, Section Quercus, Series Leucomexicanae; – Very close to Q. obtusata , but this one has thinner, glabrescent twigs, larger leaves (to 16 cm long), leaves with glandular trichomes abundant beneath, and longer peduncles (1.5-5.5 mm.) – Ressembles also Q. potosina , but this species may have abundant glandular hairs beneath, scattered glandular trichomes adaxially, the blade never longer than 10 cm, and acorn stalks longer (1.,6 to 2.5 cm).