Quercus hypoleucoides

A. Camus

Bull. Mus. Natl. Hist. Nat., sér. 2, 4: 124. 1932.

Common names: Silverleaf oak
Illustrated
Synonyms: Quercus hypoleuca Engelmann
Treatment appears in FNA Volume 3.

Trees or shrubs, evergreen, to 10 m. Bark black, deeply furrowed. Twigs dark reddish-brown, 1.5-3 mm diam., pubescent. Terminal buds light chestnut-brown, ovoid, 2.5-4.5 mm, glabrous except for ciliate scale margins, occasionally with tuft of hairs at apex. Leaves: petiole 1.5-13 mm, densely pubescent. Leaf-blade narrowly ovate to ovate or elliptic, 45-120 × 15-40 mm, base cuneate to rounded, margins strongly revolute, entire or spinose with up to 11 awns, apex acute to attenuate; surfaces abaxially densely tawny or white-tomentose, adaxially noticeably rugose, glabrous. Acorns annual or biennial; cup deeply saucer or cupshaped, 4.5-7 mm high × 6-13 mm wide, covering 1/3 nut or less, outer surface pubescent to sparsely puberulent, inner surface pubescent to floccose, scales appressed, blunt; nut ellipsoid to oblong, 8-16 × 5-10 mm, glabrous, scar diam. 2.5-5.5 mm.


Phenology: Flowering spring.
Habitat: Common in moist canyons and on ridges
Elevation: 1500-2700 m

Distribution

V3 863-distribution-map.gif

Ariz., N.Mex., Tex., n Mexico

Discussion

Quercus hypoleucoides reportedly hybridizes with Q. gravesii (Q. ×inconstans E. J. Palmer [= Q. livermorensis C. H. Muller]) (see C. H. Muller 1951). Several specimens from Pima County, Arizona, fall outside the range of typical Q. hypoleucoides, suggesting hybridization with the Mexican Q. mcvaughii Spellenberg (R. Spellenberg 1992).

Selected References

None.

Lower Taxa

None.
... more about "Quercus hypoleucoides"
biennial +  and annual +
acute +  and attenuate +
Kevin C. Nixon +
A. Camus +
cuneate;rounded +
2-6-lobed +
pistillate +, capitate +  and spicate +
Silverleaf oak +
connate +  and distinct +
starchy +  and fleshy +
tuberculate +
cup-shaped +
×6-13 +, 4.5mm +  and 7mm +
multibracteate +, spiny +  and scaly +
Ariz. +, N.Mex. +, Tex. +  and n Mexico +
1500-2700 m +
pistillate +  and staminate +
biennial +, annual +  and maturation +
1-seeded +  and winged +
in groups +  and enclosed +
Common in moist canyons and on ridges +
pistillate +, spicate +  and staminate +
pubescent +  and floccose +
silky-tomentose +
4.5 cm45 mm <br />0.045 m <br /> (12 cm120 mm <br />0.12 m <br />) +
narrowly ovate +  and ovate or elliptic +
arranged +  and alternate +
spinose +  and entire +
toothed +  and entire +
0.8 cm8 mm <br />0.008 m <br /> (1.6 cm16 mm <br />0.016 m <br />) +
ellipsoid +  and oblong +
0.5 cm5 mm <br />0.005 m <br /> (1 cm10 mm <br />0.01 m <br />) +
pubescent +  and sparsely puberulent +
0.15 cm1.5 mm <br />0.0015 m <br /> (1.3 cm13 mm <br />0.013 m <br />) +
Flowering spring. +
Bull. Mus. Natl. Hist. Nat., sér. +
distinct +
few-to-many +
reduced +
0.25 cm2.5 mm <br />0.0025 m <br /> (0.55 cm5.5 mm <br />0.0055 m <br />) +
anastomosing +, branching +  and unbranched +
Illustrated +
inconspicuous +
distinct +
linear-spatulate +
glabrous +  and white-tomentose +
Quercus hypoleuca +
Quercus hypoleucoides +
Quercus sect. Lobatae +
species +
light chestnut-brown +
0.25 cm2.5 mm <br />0.0025 m <br /> (0.45 cm4.5 mm <br />0.0045 m <br />) +
bristle-tipped +
dark reddish-brown +
0.15 cm1.5 mm <br />0.0015 m <br /> (0.3 cm3 mm <br />0.003 m <br />) +
shrub +  and tree +