| Quercus potosina | |
| Author |
Trel. 1924 Mem. Natl. Acad. Sci. 20: 84 Diagnosis here |
| Synonyms | potosina f. exilis Trel. 1924 potosina f. aperta Trel. 1924 jaralensis Trel. 1924 Diagnosis here |
| Local names | quebracho;
|
| Range | Mexico
(Durango, Zacatecas, San Luis Potosi, Jalisco, Chihuahua, Aguacalientes,
Guanajuato, Querétaro, Tamaulipas); |
| Growth habit | 3-7
m tall, trunk to 15-30 cm in diameter; often forming 1-3 m tall thickets;
|
| Leaves | 3-4.5
cm long, 1.4-2.3 cm wide; evergreen or lately deciduous; thick, coriaceous;
oboval to elliptic; apex obtuse to acute, with a mucronate tooth; base
subcordate auricled to rounded, sometimes asymmetrical; margin thick,
remotely revolute or not at all, cartilaginous, serrate-dentate with 4-5
pairs of strongly mucronate teeth on the apical 3/4; dark green or yellowish
green, lustrous above, with scattered, sessile, stellate hairs and long
(to 0.2 mm) glandular ones, glabrescent; beneath paler, with sessil fascicled
trichomes and abundant glandular trichomes covering the whole surface
of the underside but leaving the epidermis visible; 4-7 vein pairs, straight,
reddish and impressed above, prominent beneath ; epidermis glaucous, papillose
; petiole hairy, reddish, 3-7 mm long; |
| Flowers | in April; male catkins 2-3 cm long, with numerous flowers; pistillate inflorescences less than 1-2 cm long, with 1-4 flowers scattered or clustered on a tomentose stalk 1-2 cm long; |
| Fruits | acorn
1.2-1.5 cm long; ovoid; mucronate; 1-2 together or more; cup 0.8-1.2 cm
in diameter, sessile , with margin not rolled inside and pointed, woolly
scales; enclosing 1/2 of nut; maturing in 1 year in September to November;
|
|
Bark, twigs and |
bark grey, scaly; twig rather thick (1.5-3 mm), reddish, pubescent; bud ovoid or globose, hairy, glabrescent, 3 mm long; stipules 6-10 mm long, pubescent, persistent around terminal bud. |
| Hardiness zone, habitat | not quite hardy; prefers dry places; |
| Miscellaneous | --
A. Camus : n° 254 ; -- Sub-genus Quercus, Section Quercus, Series Leucomexicanae; -- Resembles Q. repanda, but this species is much smaller (0.3-1.2 m), has the tomentum of the underside of the leaf that covers totally the epidermis, and the glandular trichomes adaxially are less than 0.05 mm long. -- Possible confusion with Q. greggii, but this species has strongly coriaceous, stiff leaves, with markedly revolute margin with 2-3 veins pairs, and the abaxial face has a woolly, weakly yellowish tomentum. |
| Subspecies and varieties |
fo.
aperta and fo. exilis Trel. 1924 |
| Pictures |
|
