|Author||Trel. 1924 Mem. Natl. Acad. Sci. 20: 188 1924.
|Synonyms||alamarensis C.H.Mull. 1936 Diagnosis here|
graciliformis C.H.Mull 1934
graciliformis f. parvilobata (C.H.Mull.) C.H.Mull. 1940
graciliformis var. parvilobata C.H.Mull. 1934
graciliramis C.H.Mull. 1936 (A.Camus n° 393) Diagnosis here
karwinskii Trel. 1924
|Local names||chisos oak; slender oak; canby oak; graceful oak;|
|Range||Mexico (Coahuila, Nuevo Leon, Tamaulipas); Texas (Chisos Mountains ) ; from 0 to 2100 m in rocky canyons ; restricted area;|
|Growth habit||4-15 m tall, with trunk 20-50 cm in diameter; long flexible branches somewhat drooping;|
|Leaves||6-10 x 2-4 cm; semi-evergreen or lately deciduous; thick, subleathery; lanceolate to narrowly ovate; apex pointed, attenuate, bristle-tipped; base acute, attenuate or cuneate; margin thick, flat or slightly revolute, with 5-6 pairs of bristle-tipped, short teeth (from base to apex, or only on the apical 2/3) with shallow sinuses, or sometimes entire; dark shiny green above, hairless or sometimes with shorts stellate hairs, and glandular hairs mostly along veins; dull, yellowish-green beneath, glabrous or with axil tufts; 5-7 vein pairs, mostly straight; epidermis slightly papillose ; petiole hairless, slender, flexible, 1-2 cm long;|
male catkins pubescent, 3-5 cm long, with 20-30 flowers with 5-6 stamens and glabrous anthers; pistillate ones 0.5-1 cm long, 1 or 2-flowered;
|Fruits||acorn 1-1.5 cm, ovoid; stalkless or nearly so; singly or to 3 together; cup very shallow covering 1/2 or 1/3 of nut, with nearly flat scales; maturing in 1 year;|
Bark, twigs and
|bark brown green, smooth, becoming dark grey, warty, sulcate; twig red brown, shiny, thin (1-2 mm in diameter), soon glabrous, with rare, light lenticels; terminal bud red brown, ovoid, 1.5-3 mm, shortly ciliate;|
|Hardiness zone, habitat||hardy zone 7; prefers dry, rocky soils;|
|Miscellaneous||-- A. Camus : n°
-- Sub-genus Quercus, section Lobatae, sub-section Acutifoliae;
-- confusion is possible with Q. albocincta, which has ovate or elliptic leaves, more veins pairs, longer teeth, longer bristle-tips and longer petioles.
--- Q.canbyi has been described as a variety of Q.graciliformis
in the south of its range (North Mexico), and differs from the type
in having acorns maturing in 1 year, less lobes (4 pairs instead of 5...), and
a shallower cup. In fact, it seems that it is nothing but a geographical form...For
today's Mexican Authors (Silvia Romero Rangel, 2006),
the accepted name is Q.canbyi, and Q.graciliformis is the synonym...
--- Q.alamarensis :
for today's Mexican Authors (Susana
Valencia-Avalos, 2004), this taxon described by Muller is doubfull, maybe a hybrid
or a morphological, isolated variation...